diff --git a/avogadro/calc/lennardjones.cpp b/avogadro/calc/lennardjones.cpp
index da7f6cfa25..383a05dbcf 100644
--- a/avogadro/calc/lennardjones.cpp
+++ b/avogadro/calc/lennardjones.cpp
@@ -12,8 +12,8 @@
 namespace Avogadro::Calc {
 
 LennardJones::LennardJones()
-  : m_vdw(true), m_depth(100.0), m_exponent(6), m_cell(nullptr),
-    m_molecule(nullptr)
+  : m_molecule(nullptr), m_cell(nullptr), m_vdw(true), m_depth(100.0),
+    m_exponent(6)
 {
   // defined for 1-118
   for (unsigned int i = 1; i <= 118; ++i) {
diff --git a/avogadro/core/mesh.cpp b/avogadro/core/mesh.cpp
index 6f6ad8089d..196610b09c 100644
--- a/avogadro/core/mesh.cpp
+++ b/avogadro/core/mesh.cpp
@@ -19,9 +19,9 @@ Mesh::Mesh() : m_stable(true), m_other(0), m_cube(0), m_lock(new Mutex)
 
 Mesh::Mesh(const Mesh& other)
   : m_vertices(other.m_vertices), m_normals(other.m_normals),
-    m_colors(other.m_colors), m_name(other.m_name), m_stable(true),
-    m_isoValue(other.m_isoValue), m_other(other.m_other), m_cube(other.m_cube),
-    m_lock(new Mutex), m_triangles(other.m_triangles)
+    m_colors(other.m_colors), m_triangles(other.m_triangles),
+    m_name(other.m_name), m_stable(true), m_isoValue(other.m_isoValue),
+    m_other(other.m_other), m_cube(other.m_cube), m_lock(new Mutex)
 {
 }
 
@@ -60,7 +60,6 @@ const Vector3f* Mesh::vertex(int n) const
   return &(m_vertices[n * 3]);
 }
 
-
 bool Mesh::setTriangles(const Core::Array<Vector3f>& values)
 {
   m_triangles.clear();
@@ -68,12 +67,11 @@ bool Mesh::setTriangles(const Core::Array<Vector3f>& values)
   return true;
 }
 
-const Core::Array<Vector3f>&Mesh::triangles() const
+const Core::Array<Vector3f>& Mesh::triangles() const
 {
   return m_triangles;
 }
 
-
 bool Mesh::setVertices(const Core::Array<Vector3f>& values)
 {
   m_vertices.clear();
@@ -86,7 +84,7 @@ bool Mesh::addVertices(const Core::Array<Vector3f>& values)
   if (m_vertices.capacity() < m_vertices.size() + values.size())
     m_vertices.reserve(m_vertices.capacity() * 2);
   if (values.size() % 3 == 0) {
-    for (const auto & value : values)
+    for (const auto& value : values)
       m_vertices.push_back(value);
     return true;
   } else {
@@ -116,7 +114,7 @@ bool Mesh::addNormals(const Core::Array<Vector3f>& values)
   if (m_normals.capacity() < m_normals.size() + values.size())
     m_normals.reserve(m_normals.capacity() * 2);
   if (values.size() % 3 == 0) {
-    for (const auto & value : values)
+    for (const auto& value : values)
       m_normals.push_back(value);
     return true;
   } else {
@@ -184,7 +182,8 @@ Mesh& Mesh::operator=(const Mesh& other)
   return *this;
 }
 
-void Mesh::smooth(int iterationCount) {
+void Mesh::smooth(int iterationCount)
+{
   if (m_vertices.empty() || iterationCount <= 0)
     return;
 
@@ -206,10 +205,10 @@ void Mesh::smooth(int iterationCount) {
   // Remove duplicate neighbors and sort for faster lookups later (if needed)
   for (auto& neighbors : adjacencyList) {
     std::sort(neighbors.begin(), neighbors.end());
-    neighbors.erase(std::unique(neighbors.begin(), neighbors.end()), neighbors.end());
+    neighbors.erase(std::unique(neighbors.begin(), neighbors.end()),
+                    neighbors.end());
   }
 
-
   float weight = 1.0f;
   for (int iteration = 0; iteration < iterationCount; ++iteration) {
     Array<Vector3f> newVertices = m_vertices; // Store smoothed vertices
@@ -229,7 +228,6 @@ void Mesh::smooth(int iterationCount) {
     m_vertices = newVertices; // Update vertices after processing all
   }
 
-
   m_normals.clear();
   m_normals.resize(m_vertices.size(), Vector3f(0.0f, 0.0f, 0.0f));
 
@@ -246,8 +244,7 @@ void Mesh::smooth(int iterationCount) {
     m_normals[i] += triangleNormal;
     m_normals[j] += triangleNormal;
     m_normals[k] += triangleNormal;
-
-   }
+  }
 
   for (auto& normal : m_normals) {
     normal.normalize();
diff --git a/avogadro/core/molecule.cpp b/avogadro/core/molecule.cpp
index eed67bf9c5..7c271e336e 100644
--- a/avogadro/core/molecule.cpp
+++ b/avogadro/core/molecule.cpp
@@ -46,9 +46,8 @@ Molecule::Molecule(const Molecule& other)
     m_basisSet(other.m_basisSet ? other.m_basisSet->clone() : nullptr),
     m_unitCell(other.m_unitCell ? new UnitCell(*other.m_unitCell) : nullptr),
     m_residues(other.m_residues), m_hallNumber(other.m_hallNumber),
-    m_graph(other.m_graph), m_bondOrders(other.m_bondOrders),
-    m_atomicNumbers(other.m_atomicNumbers),
-    m_frozenAtomMask(other.m_frozenAtomMask),
+    m_frozenAtomMask(other.m_frozenAtomMask), m_graph(other.m_graph),
+    m_bondOrders(other.m_bondOrders), m_atomicNumbers(other.m_atomicNumbers),
     m_layers(LayerManager::getMoleculeLayer(this))
 {
   // Copy over any meshes
@@ -142,9 +141,8 @@ Molecule::Molecule(Molecule&& other) noexcept
     m_selectedAtoms(std::move(other.m_selectedAtoms)),
     m_meshes(std::move(other.m_meshes)), m_cubes(std::move(other.m_cubes)),
     m_residues(other.m_residues), m_hallNumber(other.m_hallNumber),
-    m_graph(other.m_graph), m_bondOrders(other.m_bondOrders),
-    m_atomicNumbers(other.m_atomicNumbers),
-    m_frozenAtomMask(other.m_frozenAtomMask),
+    m_frozenAtomMask(other.m_frozenAtomMask), m_graph(other.m_graph),
+    m_bondOrders(other.m_bondOrders), m_atomicNumbers(other.m_atomicNumbers),
     m_layers(LayerManager::getMoleculeLayer(this))
 {
   m_basisSet = other.m_basisSet;
diff --git a/avogadro/molequeue/batchjob.cpp b/avogadro/molequeue/batchjob.cpp
index e160806cdc..b30c403605 100644
--- a/avogadro/molequeue/batchjob.cpp
+++ b/avogadro/molequeue/batchjob.cpp
@@ -206,14 +206,14 @@ void BatchJob::setup()
 
   MoleQueueManager& mqManager = MoleQueueManager::instance();
   Client& client = mqManager.client();
-  connect(&client, SIGNAL(submitJobResponse(int, uint)),
-          SLOT(handleSubmissionReply(int, uint)));
-  connect(&client, SIGNAL(lookupJobResponse(int, QJsonObject)),
-          SLOT(handleLookupJobReply(int, QJsonObject)));
-  connect(&client, SIGNAL(jobStateChanged(uint, QString, QString)),
-          SLOT(handleJobStateChange(uint, QString, QString)));
-  connect(&client, SIGNAL(errorReceived(int, int, QString, QJsonValue)),
-          SLOT(handleErrorResponse(int, int, QString, QJsonValue)));
+  connect(&client, &Client::submitJobResponse, this,
+          &BatchJob::handleSubmissionReply);
+  connect(&client, &Client::lookupJobResponse, this,
+          &BatchJob::handleLookupJobReply);
+  connect(&client, &Client::jobStateChanged, this,
+          &BatchJob::handleJobStateChange);
+  connect(&client, &Client::errorReceived, this,
+          &BatchJob::handleErrorResponse);
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::MoleQueue
diff --git a/avogadro/molequeue/client/client.cpp b/avogadro/molequeue/client/client.cpp
index 17643d4d8d..781631a76e 100644
--- a/avogadro/molequeue/client/client.cpp
+++ b/avogadro/molequeue/client/client.cpp
@@ -28,14 +28,14 @@ bool Client::connectToServer(const QString& serverName)
 {
   if (!m_jsonRpcClient) {
     m_jsonRpcClient = new JsonRpcClient(this);
-    connect(m_jsonRpcClient, SIGNAL(resultReceived(QJsonObject)),
-            SLOT(processResult(QJsonObject)));
-    connect(m_jsonRpcClient, SIGNAL(notificationReceived(QJsonObject)),
-            SLOT(processNotification(QJsonObject)));
-    connect(m_jsonRpcClient, SIGNAL(errorReceived(QJsonObject)),
-            SLOT(processError(QJsonObject)));
-    connect(m_jsonRpcClient, SIGNAL(connectionStateChanged()),
-            SIGNAL(connectionStateChanged()));
+    connect(m_jsonRpcClient, &JsonRpcClient::resultReceived, this,
+            &Client::processResult);
+    connect(m_jsonRpcClient, &JsonRpcClient::notificationReceived, this,
+            &Client::processNotification);
+    connect(m_jsonRpcClient, &JsonRpcClient::errorReceived, this,
+            &Client::processError);
+    connect(m_jsonRpcClient, &JsonRpcClient::connectionStateChanged, this,
+            &Client::connectionStateChanged);
   }
 
   return m_jsonRpcClient->connectToServer(serverName);
diff --git a/avogadro/molequeue/client/jsonrpcclient.cpp b/avogadro/molequeue/client/jsonrpcclient.cpp
index 56ef521c12..9d92e17ce4 100644
--- a/avogadro/molequeue/client/jsonrpcclient.cpp
+++ b/avogadro/molequeue/client/jsonrpcclient.cpp
@@ -5,19 +5,17 @@
 
 #include "jsonrpcclient.h"
 
-#include <QtCore/QJsonDocument>
 #include <QtCore/QDataStream>
+#include <QtCore/QJsonDocument>
 #include <QtCore/QTimer>
 #include <QtNetwork/QLocalSocket>
 
 namespace Avogadro::MoleQueue {
 
-JsonRpcClient::JsonRpcClient(QObject *parent_) :
-  QObject(parent_),
-  m_packetCounter(0),
-  m_socket(nullptr)
+JsonRpcClient::JsonRpcClient(QObject* parent_)
+  : QObject(parent_), m_packetCounter(0), m_socket(nullptr)
 {
-  connect(this, SIGNAL(newPacket(QByteArray)), SLOT(readPacket(QByteArray)),
+  connect(this, &JsonRpcClient::newPacket, this, &JsonRpcClient::readPacket,
           Qt::QueuedConnection);
 }
 
@@ -34,13 +32,12 @@ bool JsonRpcClient::isConnected() const
     return m_socket->isOpen();
 }
 
-bool JsonRpcClient::connectToServer(const QString &serverName_)
+bool JsonRpcClient::connectToServer(const QString& serverName_)
 {
   if (m_socket && m_socket->isOpen()) {
     if (m_socket->serverName() == serverName_) {
       return false;
-    }
-    else {
+    } else {
       m_socket->close();
       delete m_socket;
       m_socket = nullptr;
@@ -50,13 +47,12 @@ bool JsonRpcClient::connectToServer(const QString &serverName_)
   // New connection.
   if (m_socket == nullptr) {
     m_socket = new QLocalSocket(this);
-    connect(m_socket, SIGNAL(readyRead()), this, SLOT(readSocket()));
+    connect(m_socket, &QIODevice::readyRead, this, &JsonRpcClient::readSocket);
   }
 
   if (serverName_.isEmpty()) {
     return false;
-  }
-  else {
+  } else {
     m_socket->connectToServer(serverName_);
     return isConnected();
   }
@@ -84,7 +80,7 @@ QJsonObject JsonRpcClient::emptyRequest()
   return request;
 }
 
-bool JsonRpcClient::sendRequest(const QJsonObject &request)
+bool JsonRpcClient::sendRequest(const QJsonObject& request)
 {
   if (!m_socket)
     return false;
@@ -103,16 +99,14 @@ void JsonRpcClient::readPacket(const QByteArray message)
   QJsonDocument reader = QJsonDocument::fromJson(message, &error);
 
   if (error.error != QJsonParseError::NoError) {
-    emit badPacketReceived("Unparsable message received\n:"
-                           + error.errorString() + "\nContent: " + message);
+    emit badPacketReceived("Unparsable message received\n:" +
+                           error.errorString() + "\nContent: " + message);
     return;
-  }
-  else if (!reader.isObject()) {
+  } else if (!reader.isObject()) {
     // We need a valid object, something bad happened.
     emit badPacketReceived("Packet did not contain a valid JSON object.");
     return;
-  }
-  else {
+  } else {
     QJsonObject root = reader.object();
     if (root["method"] != QJsonValue::Null) {
       if (root["id"] != QJsonValue::Null)
@@ -123,8 +117,7 @@ void JsonRpcClient::readPacket(const QByteArray message)
     if (root["result"] != QJsonValue::Null) {
       // This is a result packet, and should emit a signal.
       emit resultReceived(root);
-    }
-    else if (root["error"] != QJsonValue::Null) {
+    } else if (root["error"] != QJsonValue::Null) {
       emit errorReceived(root);
     }
   }
@@ -138,8 +131,8 @@ void JsonRpcClient::readSocket()
     stream >> json;
     emit newPacket(json);
     if (m_socket->bytesAvailable() > 0)
-      QTimer::singleShot(0, this, SLOT(readSocket()));
+      QTimer::singleShot(0, this, &JsonRpcClient::readSocket);
   }
 }
 
-} // End namespace Avogadro
+} // namespace Avogadro::MoleQueue
diff --git a/avogadro/molequeue/inputgeneratordialog.cpp b/avogadro/molequeue/inputgeneratordialog.cpp
index 447a518bb0..048df963cd 100644
--- a/avogadro/molequeue/inputgeneratordialog.cpp
+++ b/avogadro/molequeue/inputgeneratordialog.cpp
@@ -16,7 +16,8 @@ InputGeneratorDialog::InputGeneratorDialog(QWidget* parent_)
   : QDialog(parent_), ui(new Ui::InputGeneratorDialog)
 {
   ui->setupUi(this);
-  connect(ui->widget, SIGNAL(closeClicked()), SLOT(accept()));
+  connect(ui->widget, &InputGeneratorWidget::closeClicked, this,
+          &QDialog::accept);
 }
 
 InputGeneratorDialog::InputGeneratorDialog(const QString& scriptFileName,
@@ -24,7 +25,8 @@ InputGeneratorDialog::InputGeneratorDialog(const QString& scriptFileName,
   : QDialog(parent_), ui(new Ui::InputGeneratorDialog)
 {
   ui->setupUi(this);
-  connect(ui->widget, SIGNAL(closeClicked()), SLOT(accept()));
+  connect(ui->widget, &InputGeneratorWidget::closeClicked, this,
+          &QDialog::accept);
   this->setInputGeneratorScript(scriptFileName);
 }
 
@@ -68,4 +70,4 @@ void InputGeneratorDialog::setMolecule(Molecule* mol)
   ui->widget->setMolecule(mol);
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::MoleQueue
diff --git a/avogadro/molequeue/inputgeneratorwidget.cpp b/avogadro/molequeue/inputgeneratorwidget.cpp
index 4c1ae8914b..782484276d 100644
--- a/avogadro/molequeue/inputgeneratorwidget.cpp
+++ b/avogadro/molequeue/inputgeneratorwidget.cpp
@@ -68,8 +68,10 @@ void InputGeneratorWidget::setMolecule(QtGui::Molecule* mol)
     // make sure to call the base class method
     QtGui::JsonWidget::setMolecule(mol);
 
-    connect(mol, SIGNAL(changed(unsigned int)), SLOT(updatePreviewText()));
-    connect(mol, SIGNAL(changed(unsigned int)), SLOT(updateTitlePlaceholder()));
+    connect(mol, &QtGui::Molecule::changed, this,
+            &InputGeneratorWidget::updatePreviewText);
+    connect(mol, &QtGui::Molecule::changed, this,
+            &InputGeneratorWidget::updateTitlePlaceholder);
   }
 
   updateTitlePlaceholder();
@@ -132,7 +134,8 @@ void InputGeneratorWidget::showEvent(QShowEvent* e)
   // Update the preview text if an update was requested while hidden. Use a
   // single shot to allow the dialog to show before popping up any warnings.
   if (m_updatePending)
-    QTimer::singleShot(0, this, SLOT(updatePreviewTextImmediately()));
+    QTimer::singleShot(0, this,
+                       &InputGeneratorWidget::updatePreviewTextImmediately);
 }
 
 void InputGeneratorWidget::updatePreviewText()
@@ -141,7 +144,8 @@ void InputGeneratorWidget::updatePreviewText()
     return;
 
   m_updatePending = true;
-  QTimer::singleShot(250, this, SLOT(updatePreviewTextImmediately()));
+  QTimer::singleShot(250, this,
+                     &InputGeneratorWidget::updatePreviewTextImmediately);
 }
 
 void InputGeneratorWidget::updatePreviewTextImmediately()
@@ -234,7 +238,8 @@ void InputGeneratorWidget::updatePreviewTextImmediately()
     auto* edit = new QTextEdit(this);
     edit->setObjectName(fileName);
     edit->setFontFamily("monospace");
-    connect(edit, SIGNAL(textChanged()), this, SLOT(textEditModified()));
+    connect(edit, &QTextEdit::textChanged, this,
+            &InputGeneratorWidget::textEditModified);
     m_ui->tabWidget->addTab(edit, fileName);
     m_textEdits.insert(fileName, edit);
   }
@@ -623,22 +628,26 @@ QJsonObject InputGeneratorWidget::promptForBatchJobOptions() const
 
 void InputGeneratorWidget::connectButtons()
 {
-  connect(m_ui->debugCheckBox, SIGNAL(toggled(bool)), &m_inputGenerator,
-          SLOT(setDebug(bool)));
-  connect(m_ui->debugCheckBox, SIGNAL(toggled(bool)),
-          SLOT(updatePreviewText()));
-  connect(m_ui->defaultsButton, SIGNAL(clicked()), SLOT(defaultsClicked()));
-  connect(m_ui->generateButton, SIGNAL(clicked()), SLOT(generateClicked()));
-  connect(m_ui->closeButton, SIGNAL(clicked()), SIGNAL(closeClicked()));
-  connect(m_ui->warningTextButton, SIGNAL(clicked()),
-          SLOT(toggleWarningText()));
+  connect(m_ui->debugCheckBox, &QAbstractButton::toggled, &m_inputGenerator,
+          &InputGenerator::setDebug);
+  connect(m_ui->debugCheckBox, &QAbstractButton::toggled, this,
+          &InputGeneratorWidget::updatePreviewText);
+  connect(m_ui->defaultsButton, &QAbstractButton::clicked, this,
+          &InputGeneratorWidget::defaultsClicked);
+  connect(m_ui->generateButton, &QAbstractButton::clicked, this,
+          &InputGeneratorWidget::generateClicked);
+  connect(m_ui->closeButton, &QAbstractButton::clicked, this,
+          &InputGeneratorWidget::closeClicked);
+  connect(m_ui->warningTextButton, &QAbstractButton::clicked, this,
+          &InputGeneratorWidget::toggleWarningText);
 
   // disable the compute button if Molequeue is not running
   MoleQueueManager& mqManager = MoleQueueManager::instance();
   if (!mqManager.connectIfNeeded()) {
     m_ui->computeButton->setEnabled(false);
   } else {
-    connect(m_ui->computeButton, SIGNAL(clicked()), SLOT(computeClicked()));
+    connect(m_ui->computeButton, &QAbstractButton::clicked, this,
+            &InputGeneratorWidget::computeClicked);
   }
 }
 
diff --git a/avogadro/molequeue/molequeuedialog.cpp b/avogadro/molequeue/molequeuedialog.cpp
index 6cfaf7ff06..3b2f4609b4 100644
--- a/avogadro/molequeue/molequeuedialog.cpp
+++ b/avogadro/molequeue/molequeuedialog.cpp
@@ -80,7 +80,8 @@ MoleQueueDialog::SubmitStatus MoleQueueDialog::submitJob(
           return SubmissionSuccessful;
 
         // Update progress dialog
-        progress.setLabelText(tr("Waiting for job %1 “%2” to finish…", "%1 = job ID, %2 = description")
+        progress.setLabelText(tr("Waiting for job %1 “%2” to finish…",
+                                 "%1 = job ID, %2 = description")
                                 .arg(dlg.widget().moleQueueId())
                                 .arg(jobTemplate.description()));
         progress.setCancelButtonText(tr("Stop waiting"));
@@ -106,8 +107,8 @@ MoleQueueDialog::SubmitStatus MoleQueueDialog::submitJob(
         progress.setCancelButton(nullptr);
 
         // Job completed -- overwrite job template with updated job details.
-        connect(&dlg.widget(), SIGNAL(jobUpdated(MoleQueue::JobObject)),
-                &dlg.widget(), SLOT(setJobTemplate(MoleQueue::JobObject)));
+        connect(&dlg.widget(), &MoleQueueWidget::jobUpdated, &dlg.widget(),
+                &MoleQueueWidget::setJobTemplate);
         QList<MetaMethod> lookupSignal;
         lookupSignal << MetaMethod(&dlg.widget(),
                                    SIGNAL(jobUpdated(MoleQueue::JobObject)));
@@ -124,9 +125,10 @@ MoleQueueDialog::SubmitStatus MoleQueueDialog::submitJob(
         return JobFinished;
       } else {
         progress.hide();
-        QMessageBox::warning(&dlg, tr("Error Submitting Job"),
-                             tr("The job has been rejected by MoleQueue: %1", "%1 = error")
-                               .arg(dlg.widget().submissionError()));
+        QMessageBox::warning(
+          &dlg, tr("Error Submitting Job"),
+          tr("The job has been rejected by MoleQueue: %1", "%1 = error")
+            .arg(dlg.widget().submissionError()));
         continue;
       }
     } else {
@@ -180,7 +182,7 @@ bool MoleQueueDialog::waitForSignal(const QList<MetaMethod>& signalList,
   QTimer limiter;
   if (msTimeout >= 0) {
     limiter.setSingleShot(true);
-    connect(&limiter, SIGNAL(timeout()), &waiter, SLOT(quit()));
+    connect(&limiter, &QTimer::timeout, &waiter, &QEventLoop::quit);
     limiter.start(msTimeout);
   }
 
@@ -200,4 +202,4 @@ void MoleQueueDialog::done(int r)
   }
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::MoleQueue
diff --git a/avogadro/molequeue/molequeuemanager.cpp b/avogadro/molequeue/molequeuemanager.cpp
index bef35b1749..8e319adc06 100644
--- a/avogadro/molequeue/molequeuemanager.cpp
+++ b/avogadro/molequeue/molequeuemanager.cpp
@@ -12,8 +12,8 @@ MoleQueueManager* MoleQueueManager::m_instance = nullptr;
 MoleQueueManager::MoleQueueManager(QObject* parent_)
   : QObject(parent_), m_client(this), m_queueModel(this)
 {
-  connect(&m_client, SIGNAL(queueListReceived(QJsonObject)),
-          SLOT(updateQueueModel(QJsonObject)));
+  connect(&m_client, &Client::queueListReceived, this,
+          &MoleQueueManager::updateQueueModel);
 }
 
 MoleQueueManager& MoleQueueManager::instance()
@@ -63,4 +63,4 @@ void MoleQueueManager::updateQueueModel(const QJsonObject& json)
   emit queueListUpdated();
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::MoleQueue
diff --git a/avogadro/molequeue/molequeuewidget.cpp b/avogadro/molequeue/molequeuewidget.cpp
index 6034239897..472b1ac6e0 100644
--- a/avogadro/molequeue/molequeuewidget.cpp
+++ b/avogadro/molequeue/molequeuewidget.cpp
@@ -25,8 +25,8 @@ MoleQueueWidget::MoleQueueWidget(QWidget* parent_)
 {
   m_ui->setupUi(this);
 
-  connect(m_ui->refreshProgramsButton, SIGNAL(clicked()),
-          SLOT(refreshPrograms()));
+  connect(m_ui->refreshProgramsButton, &QAbstractButton::clicked, this,
+          &MoleQueueWidget::refreshPrograms);
 
   MoleQueueManager& mqManager = MoleQueueManager::instance();
   m_ui->queueListView->setModel(&mqManager.queueListModel());
@@ -107,8 +107,8 @@ void MoleQueueWidget::showAndSelectProgram(const QString& programName)
   MoleQueueManager& mqManager = MoleQueueManager::instance();
   setProperty("selectProgramName", programName);
 
-  connect(&mqManager, SIGNAL(queueListUpdated()),
-          SLOT(showAndSelectProgramHandler()));
+  connect(&mqManager, &MoleQueueManager::queueListUpdated, this,
+          &MoleQueueWidget::showAndSelectProgramHandler);
 
   if (mqManager.connectIfNeeded())
     mqManager.requestQueueList();
@@ -180,8 +180,8 @@ void MoleQueueWidget::showAndSelectProgramHandler()
   MoleQueueManager& mqManager = MoleQueueManager::instance();
   const QString program(property("selectProgramName").toString());
   setProperty("selectProgramName", QVariant());
-  disconnect(&mqManager, SIGNAL(queueListUpdated()), this,
-             SLOT(showAndSelectProgramHandler()));
+  disconnect(&mqManager, &MoleQueueManager::queueListUpdated, this,
+             &MoleQueueWidget::showAndSelectProgramHandler);
 
   // Get all program nodes that match the name
   QModelIndexList list(mqManager.queueListModel().findProgramIndices(program));
@@ -255,11 +255,11 @@ void MoleQueueWidget::listenForLookupJobReply(bool listen)
 {
   Client& mqClient(MoleQueueManager::instance().client());
   if (listen) {
-    connect(&mqClient, SIGNAL(lookupJobResponse(int, QJsonObject)), this,
-            SLOT(onLookupJobReply(int, QJsonObject)));
+    connect(&mqClient, &Client::lookupJobResponse, this,
+            &MoleQueueWidget::onLookupJobReply);
   } else {
-    disconnect(&mqClient, SIGNAL(lookupJobResponse(int, QJsonObject)), this,
-               SLOT(onLookupJobReply(int, QJsonObject)));
+    disconnect(&mqClient, &Client::lookupJobResponse, this,
+               &MoleQueueWidget::onLookupJobReply);
   }
 }
 
@@ -268,15 +268,15 @@ void MoleQueueWidget::listenForJobSubmitReply(bool listen)
   MoleQueue::Client& mqClient(MoleQueueManager::instance().client());
 
   if (listen) {
-    connect(&mqClient, SIGNAL(submitJobResponse(int, uint)), this,
-            SLOT(onSubmissionSuccess(int, uint)));
-    connect(&mqClient, SIGNAL(errorReceived(int, uint, QString)), this,
-            SLOT(onSubmissionFailure(int, uint, QString)));
+    connect(&mqClient, &Client::submitJobResponse, this,
+            &MoleQueueWidget::onSubmissionSuccess);
+    connect(&mqClient, &Client::errorReceived, this,
+            &MoleQueueWidget::onSubmissionFailure);
   } else {
-    disconnect(&mqClient, SIGNAL(submitJobResponse(int, uint)), this,
-               SLOT(onSubmissionSuccess(int, uint)));
-    disconnect(&mqClient, SIGNAL(errorReceived(int, uint, QString)), this,
-               SLOT(onSubmissionFailure(int, uint, QString)));
+    disconnect(&mqClient, &Client::submitJobResponse, this,
+               &MoleQueueWidget::onSubmissionSuccess);
+    disconnect(&mqClient, &Client::errorReceived, this,
+               &MoleQueueWidget::onSubmissionFailure);
   }
 }
 
@@ -285,11 +285,11 @@ void MoleQueueWidget::listenForJobStateChange(bool listen)
   MoleQueue::Client& mqClient(MoleQueueManager::instance().client());
 
   if (listen) {
-    connect(&mqClient, SIGNAL(jobStateChanged(uint, QString, QString)), this,
-            SLOT(onJobStateChange(uint, QString, QString)));
+    connect(&mqClient, &Client::jobStateChanged, this,
+            &MoleQueueWidget::onJobStateChange);
   } else {
-    disconnect(&mqClient, SIGNAL(jobStateChanged(uint, QString, QString)), this,
-               SLOT(onJobStateChange(uint, QString, QString)));
+    disconnect(&mqClient, &Client::jobStateChanged, this,
+               &MoleQueueWidget::onJobStateChange);
   }
 }
 
@@ -299,4 +299,4 @@ bool MoleQueueWidget::programSelected()
   return sel.size() > 0;
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::MoleQueue
diff --git a/avogadro/qtgui/colorbutton.cpp b/avogadro/qtgui/colorbutton.cpp
index 321a3f17ad..06feebd82f 100644
--- a/avogadro/qtgui/colorbutton.cpp
+++ b/avogadro/qtgui/colorbutton.cpp
@@ -18,7 +18,7 @@ ColorButton::ColorButton(QWidget* parent)
 {
   setMinimumSize(35, 20);
 
-  connect(this, SIGNAL(clicked()), this, SLOT(changeColor()));
+  connect(this, &QAbstractButton::clicked, this, &ColorButton::changeColor);
 }
 
 ColorButton::ColorButton(const QColor& initial, QWidget* parent)
@@ -26,7 +26,7 @@ ColorButton::ColorButton(const QColor& initial, QWidget* parent)
 {
   setMinimumSize(35, 20);
 
-  connect(this, SIGNAL(clicked()), this, SLOT(changeColor()));
+  connect(this, &QAbstractButton::clicked, this, &ColorButton::changeColor);
 }
 
 void ColorButton::changeColor()
@@ -85,4 +85,4 @@ bool ColorButton::event(QEvent* e)
   return QAbstractButton::event(e);
 }
 
-} // namespace Avogadro
\ No newline at end of file
+} // namespace Avogadro::QtGui
diff --git a/avogadro/qtgui/containerwidget.cpp b/avogadro/qtgui/containerwidget.cpp
index c7b280bc49..ebcd2cf1c7 100644
--- a/avogadro/qtgui/containerwidget.cpp
+++ b/avogadro/qtgui/containerwidget.cpp
@@ -13,10 +13,8 @@
 namespace Avogadro::QtGui {
 
 ContainerWidget::ContainerWidget(QWidget* p, Qt::WindowFlags f)
-  : QWidget(p, f)
-  , m_viewWidget(nullptr)
-  , m_label(new QLabel(QStringLiteral("   "), this))
-  , m_active(false)
+  : QWidget(p, f), m_viewWidget(nullptr),
+    m_label(new QLabel(QStringLiteral("   "), this)), m_active(false)
 {
   auto* h = new QHBoxLayout;
   h->setContentsMargins(0, 0, 0, 0);
@@ -27,13 +25,15 @@ ContainerWidget::ContainerWidget(QWidget* p, Qt::WindowFlags f)
   h->addWidget(m_label);
   h->addStretch();
   auto* button = new QPushButton(tr("Split Horizontal"), this);
-  connect(button, SIGNAL(clicked()), SIGNAL(splitHorizontal()));
+  connect(button, &QAbstractButton::clicked, this,
+          &ContainerWidget::splitHorizontal);
   h->addWidget(button);
   button = new QPushButton(tr("Split Vertical"), this);
-  connect(button, SIGNAL(clicked()), SIGNAL(splitVertical()));
+  connect(button, &QAbstractButton::clicked, this,
+          &ContainerWidget::splitVertical);
   h->addWidget(button);
   button = new QPushButton(tr("Close"), this);
-  connect(button, SIGNAL(clicked()), SIGNAL(closeView()));
+  connect(button, &QAbstractButton::clicked, this, &ContainerWidget::closeView);
   h->addWidget(button);
   v->addLayout(h);
   setLayout(v);
@@ -62,4 +62,4 @@ void ContainerWidget::setActive(bool active)
   }
 }
 
-} // End Avogadro namespace
+} // namespace Avogadro::QtGui
diff --git a/avogadro/qtgui/filebrowsewidget.cpp b/avogadro/qtgui/filebrowsewidget.cpp
index ecede6989f..6591d9812e 100644
--- a/avogadro/qtgui/filebrowsewidget.cpp
+++ b/avogadro/qtgui/filebrowsewidget.cpp
@@ -38,10 +38,11 @@ FileBrowseWidget::FileBrowseWidget(QWidget* theParent)
   m_edit->setCompleter(fsCompleter);
 
   // Connections:
-  connect(m_button, SIGNAL(clicked()), SLOT(browse()));
-  connect(m_edit, SIGNAL(textChanged(QString)), SLOT(testFileName()));
-  connect(m_edit, SIGNAL(textChanged(QString)),
-          SIGNAL(fileNameChanged(QString)));
+  connect(m_button, &QAbstractButton::clicked, this, &FileBrowseWidget::browse);
+  connect(m_edit, &QLineEdit::textChanged, this,
+          &FileBrowseWidget::testFileName);
+  connect(m_edit, &QLineEdit::textChanged, this,
+          &FileBrowseWidget::fileNameChanged);
 
   setMode(ExistingFile);
 }
diff --git a/avogadro/qtgui/gaussiansetconcurrent.cpp b/avogadro/qtgui/gaussiansetconcurrent.cpp
index 1c5f3e370a..3e3af3066f 100644
--- a/avogadro/qtgui/gaussiansetconcurrent.cpp
+++ b/avogadro/qtgui/gaussiansetconcurrent.cpp
@@ -43,7 +43,8 @@ GaussianSetConcurrent::GaussianSetConcurrent(QObject* p)
   : QObject(p), m_gaussianShells(nullptr), m_set(nullptr), m_tools(nullptr)
 {
   // Watch for the future
-  connect(&m_watcher, SIGNAL(finished()), this, SLOT(calculationComplete()));
+  connect(&m_watcher, &QFutureWatcherBase::finished, this,
+          &GaussianSetConcurrent::calculationComplete);
 }
 
 GaussianSetConcurrent::~GaussianSetConcurrent()
diff --git a/avogadro/qtgui/insertfragmentdialog.cpp b/avogadro/qtgui/insertfragmentdialog.cpp
index 34b7393130..3de53eb06c 100644
--- a/avogadro/qtgui/insertfragmentdialog.cpp
+++ b/avogadro/qtgui/insertfragmentdialog.cpp
@@ -130,21 +130,21 @@ InsertFragmentDialog::InsertFragmentDialog(QWidget* aParent, QString directory)
   m_ui->directoryTreeView->setSelectionBehavior(QAbstractItemView::SelectRows);
   m_ui->directoryTreeView->setUniformRowHeights(true);
 
-  connect(m_ui->insertFragmentButton, SIGNAL(clicked(bool)), this,
-          SLOT(activated()));
+  connect(m_ui->insertFragmentButton, &QAbstractButton::clicked, this,
+          &InsertFragmentDialog::activated);
 
-  connect(m_ui->directoryTreeView, SIGNAL(doubleClicked(const QModelIndex)),
-          this, SLOT(activated()));
+  connect(m_ui->directoryTreeView, &QAbstractItemView::doubleClicked, this,
+          &InsertFragmentDialog::activated);
 
-  connect(m_ui->directoryTreeView, SIGNAL(activated(const QModelIndex)), this,
-          SLOT(activated()));
+  connect(m_ui->directoryTreeView, &QAbstractItemView::activated, this,
+          &InsertFragmentDialog::activated);
 
-  connect(m_ui->filterLineEdit, SIGNAL(textChanged(const QString&)), this,
-          SLOT(filterTextChanged(const QString&)));
+  connect(m_ui->filterLineEdit, &QLineEdit::textChanged, this,
+          &InsertFragmentDialog::filterTextChanged);
 
   connect(m_ui->directoryTreeView->selectionModel(),
-          SIGNAL(currentChanged(const QModelIndex&, const QModelIndex&)), this,
-          SLOT(currentChanged(const QModelIndex&, const QModelIndex&)));
+          &QItemSelectionModel::currentChanged, this,
+          &InsertFragmentDialog::currentChanged);
 }
 
 InsertFragmentDialog::~InsertFragmentDialog()
diff --git a/avogadro/qtgui/jsonwidget.cpp b/avogadro/qtgui/jsonwidget.cpp
index 8f4ed59e01..9f01c90da2 100644
--- a/avogadro/qtgui/jsonwidget.cpp
+++ b/avogadro/qtgui/jsonwidget.cpp
@@ -31,8 +31,8 @@
 namespace Avogadro::QtGui {
 
 JsonWidget::JsonWidget(QWidget* parent_)
-  : QWidget(parent_), m_molecule(nullptr), m_currentLayout(nullptr),
-    m_centralWidget(nullptr), m_empty(true), m_batchMode(false)
+  : QWidget(parent_), m_molecule(nullptr), m_empty(true), m_batchMode(false),
+    m_currentLayout(nullptr), m_centralWidget(nullptr)
 {
 }
 
diff --git a/avogadro/qtgui/multiviewwidget.cpp b/avogadro/qtgui/multiviewwidget.cpp
index 25f283951e..e1afa225fb 100644
--- a/avogadro/qtgui/multiviewwidget.cpp
+++ b/avogadro/qtgui/multiviewwidget.cpp
@@ -21,10 +21,7 @@ class ActiveWidgetFilter : public QObject
   Q_OBJECT
 
 public:
-  ActiveWidgetFilter(MultiViewWidget* p = nullptr)
-    : QObject(p)
-    , m_widget(p)
-  {}
+  ActiveWidgetFilter(MultiViewWidget* p = nullptr) : QObject(p), m_widget(p) {}
 
 signals:
   void activeWidget(QWidget* widget);
@@ -46,11 +43,10 @@ class ActiveWidgetFilter : public QObject
 };
 
 MultiViewWidget::MultiViewWidget(QWidget* p, Qt::WindowFlags f)
-  : QWidget(p, f)
-  , m_factory(nullptr)
-  , m_activeWidget(nullptr)
-  , m_activeFilter(new ActiveWidgetFilter(this))
-{}
+  : QWidget(p, f), m_factory(nullptr), m_activeWidget(nullptr),
+    m_activeFilter(new ActiveWidgetFilter(this))
+{
+}
 
 MultiViewWidget::~MultiViewWidget() {}
 
@@ -172,9 +168,12 @@ void MultiViewWidget::removeView()
 ContainerWidget* MultiViewWidget::createContainer(QWidget* widget)
 {
   auto* container = new ContainerWidget;
-  connect(container, SIGNAL(splitHorizontal()), SLOT(splitHorizontal()));
-  connect(container, SIGNAL(splitVertical()), SLOT(splitVertical()));
-  connect(container, SIGNAL(closeView()), SLOT(removeView()));
+  connect(container, &ContainerWidget::splitHorizontal, this,
+          &MultiViewWidget::splitHorizontal);
+  connect(container, &ContainerWidget::splitVertical, this,
+          &MultiViewWidget::splitVertical);
+  connect(container, &ContainerWidget::closeView, this,
+          &MultiViewWidget::removeView);
 
   if (widget) {
     container->setViewWidget(widget);
@@ -189,7 +188,8 @@ ContainerWidget* MultiViewWidget::createContainer(QWidget* widget)
       auto* button = new QPushButton(name);
       button->setProperty("name", name);
       button->setToolTip(tr("Create a new view"));
-      connect(button, SIGNAL(clicked()), SLOT(createView()));
+      connect(button, &QAbstractButton::clicked, this,
+              &MultiViewWidget::createView);
       auto* h = new QHBoxLayout;
       h->addStretch();
       h->addWidget(button);
@@ -238,6 +238,6 @@ void MultiViewWidget::splitView(Qt::Orientation orient,
   }
 }
 
-} // End Avogadro namespace
+} // namespace Avogadro::QtGui
 
 #include "multiviewwidget.moc"
diff --git a/avogadro/qtgui/periodictableview.cpp b/avogadro/qtgui/periodictableview.cpp
index 8346ac7a89..2b6b55f8c8 100644
--- a/avogadro/qtgui/periodictableview.cpp
+++ b/avogadro/qtgui/periodictableview.cpp
@@ -30,7 +30,8 @@ PeriodicTableView::PeriodicTableView(QWidget* parent_)
   setRenderHint(QPainter::Antialiasing);
   setWindowTitle(tr("Periodic Table"));
   resize(490, 270);
-  connect(table, SIGNAL(elementChanged(int)), this, SLOT(elementClicked(int)));
+  connect(table, &PeriodicTableScene::elementChanged, this,
+          &PeriodicTableView::elementClicked);
 }
 
 PeriodicTableView::~PeriodicTableView()
@@ -68,7 +69,7 @@ void PeriodicTableView::keyPressEvent(QKeyEvent* event_)
     // This is the first character typed.
     // Wait for 2 seconds, then clear the buffer,
     // this ensures we can get multi-character elements.
-    QTimer::singleShot(2000, this, SLOT(clearKeyPressBuffer()));
+    QTimer::singleShot(2000, this, &PeriodicTableView::clearKeyPressBuffer);
   }
 
   if (event_->key() == Qt::Key_Escape || event_->key() == Qt::Key_Return ||
@@ -147,4 +148,4 @@ void PeriodicTableView::resizeEvent(QResizeEvent* e)
   setTransform(scaleTransform);
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtGui
diff --git a/avogadro/qtgui/scenepluginmodel.cpp b/avogadro/qtgui/scenepluginmodel.cpp
index 739e6712d0..415d7d3d98 100644
--- a/avogadro/qtgui/scenepluginmodel.cpp
+++ b/avogadro/qtgui/scenepluginmodel.cpp
@@ -153,7 +153,8 @@ void ScenePluginModel::addItem(ScenePlugin* item)
   if (!m_scenePlugins.contains(item)) {
     m_scenePlugins.append(item);
     item->setParent(this);
-    connect(item, SIGNAL(drawablesChanged()), SIGNAL(pluginConfigChanged()));
+    connect(item, &ScenePlugin::drawablesChanged, this,
+            &ScenePluginModel::pluginConfigChanged);
   }
 }
 
diff --git a/avogadro/qtgui/slatersetconcurrent.cpp b/avogadro/qtgui/slatersetconcurrent.cpp
index baeb3d69ef..49c6c21e7b 100644
--- a/avogadro/qtgui/slatersetconcurrent.cpp
+++ b/avogadro/qtgui/slatersetconcurrent.cpp
@@ -32,7 +32,8 @@ SlaterSetConcurrent::SlaterSetConcurrent(QObject* p)
   : QObject(p), m_shells(nullptr), m_set(nullptr), m_tools(nullptr)
 {
   // Watch for the future
-  connect(&m_watcher, SIGNAL(finished()), this, SLOT(calculationComplete()));
+  connect(&m_watcher, &QFutureWatcherBase::finished, this,
+          &SlaterSetConcurrent::calculationComplete);
 }
 
 SlaterSetConcurrent::~SlaterSetConcurrent()
diff --git a/avogadro/qtplugins/3dmol/3dmol.cpp b/avogadro/qtplugins/3dmol/3dmol.cpp
index f75b3f4116..19d17d0bbb 100644
--- a/avogadro/qtplugins/3dmol/3dmol.cpp
+++ b/avogadro/qtplugins/3dmol/3dmol.cpp
@@ -29,7 +29,7 @@ ThreeDMol::ThreeDMol(QObject* parent_)
 {
   m_action->setEnabled(true);
   m_action->setText("&3DMol HTML Snippet…");
-  connect(m_action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(m_action, &QAction::triggered, this, &ThreeDMol::showDialog);
 }
 
 QString ThreeDMol::description() const
diff --git a/avogadro/qtplugins/3dmol/3dmoldialog.cpp b/avogadro/qtplugins/3dmol/3dmoldialog.cpp
index a148f15535..640c1b5cd6 100644
--- a/avogadro/qtplugins/3dmol/3dmoldialog.cpp
+++ b/avogadro/qtplugins/3dmol/3dmoldialog.cpp
@@ -55,10 +55,13 @@ void ThreeDMolDialog::setMolecule(QtGui::Molecule* mol)
   if (!m_molecule)
     return;
 
-  connect(m_molecule, SIGNAL(changed(unsigned int)), SLOT(updateLabels()));
-  connect(m_molecule, SIGNAL(destroyed()), SLOT(moleculeDestroyed()));
-  connect(m_ui->closeButton, SIGNAL(clicked()), SLOT(close()));
-  connect(m_ui->copyButton, SIGNAL(clicked()), SLOT(copyToClipboard()));
+  connect(m_molecule, &QtGui::Molecule::changed, this,
+          &ThreeDMolDialog::updateLabels);
+  connect(m_molecule, &QObject::destroyed, this,
+          &ThreeDMolDialog::moleculeDestroyed);
+  connect(m_ui->closeButton, &QAbstractButton::clicked, this, &QWidget::close);
+  connect(m_ui->copyButton, &QAbstractButton::clicked, this,
+          &ThreeDMolDialog::copyToClipboard);
 
   updateLabels();
 }
@@ -123,4 +126,4 @@ void ThreeDMolDialog::copyToClipboard()
   QApplication::clipboard()->setText(m_ui->plainTextEdit->toPlainText());
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/alchemy/alchemy.cpp b/avogadro/qtplugins/alchemy/alchemy.cpp
index a9bb60dff5..930cca090d 100644
--- a/avogadro/qtplugins/alchemy/alchemy.cpp
+++ b/avogadro/qtplugins/alchemy/alchemy.cpp
@@ -21,8 +21,8 @@ using Core::Array;
 using Core::Elements;
 
 Alchemy::Alchemy(QObject* parent_)
-  : Avogadro::QtGui::ExtensionPlugin(parent_),
-    m_action(new QAction(tr("Change Elements…"), this)), m_molecule(nullptr)
+  : Avogadro::QtGui::ExtensionPlugin(parent_), m_molecule(nullptr),
+    m_action(new QAction(tr("Change Elements…"), this))
 {
   m_action->setProperty("menu priority", 750);
 
diff --git a/avogadro/qtplugins/aligntool/aligntool.cpp b/avogadro/qtplugins/aligntool/aligntool.cpp
index b90fc3a9b5..e543232158 100644
--- a/avogadro/qtplugins/aligntool/aligntool.cpp
+++ b/avogadro/qtplugins/aligntool/aligntool.cpp
@@ -43,8 +43,8 @@ namespace Avogadro::QtPlugins {
 
 AlignTool::AlignTool(QObject* parent_)
   : QtGui::ToolPlugin(parent_), m_activateAction(new QAction(this)),
-    m_molecule(nullptr), m_toolWidget(nullptr), m_renderer(nullptr),
-    m_alignType(0), m_axis(0)
+    m_molecule(nullptr), m_renderer(nullptr), m_axis(0), m_alignType(0),
+    m_toolWidget(nullptr)
 {
   m_activateAction->setText(tr("Align"));
   m_activateAction->setToolTip(
@@ -90,7 +90,7 @@ QWidget* AlignTool::toolWidget() const
     // Button to actually perform actions
     auto* buttonAlign = new QPushButton(m_toolWidget);
     buttonAlign->setText(tr("Align"));
-    connect(buttonAlign, SIGNAL(clicked()), this, SLOT(align()));
+    connect(buttonAlign, &QAbstractButton::clicked, this, &AlignTool::align);
 
     auto* gridLayout = new QGridLayout();
     gridLayout->addWidget(labelAxis, 0, 0, 1, 1, Qt::AlignRight);
@@ -112,8 +112,8 @@ QWidget* AlignTool::toolWidget() const
     connect(comboAxis, SIGNAL(currentIndexChanged(int)), this,
             SLOT(axisChanged(int)));
 
-    connect(m_toolWidget, SIGNAL(destroyed()), this,
-            SLOT(toolWidgetDestroyed()));
+    connect(m_toolWidget, &QObject::destroyed, this,
+            &AlignTool::toolWidgetDestroyed);
   }
 
   return m_toolWidget;
diff --git a/avogadro/qtplugins/apbs/apbs.cpp b/avogadro/qtplugins/apbs/apbs.cpp
index 719d3e3c1d..d7964c1ad8 100644
--- a/avogadro/qtplugins/apbs/apbs.cpp
+++ b/avogadro/qtplugins/apbs/apbs.cpp
@@ -30,12 +30,12 @@ Apbs::Apbs(QObject* parent_)
 {
   auto* action = new QAction(this);
   action->setText(tr("Run APBS…"));
-  connect(action, SIGNAL(triggered()), this, SLOT(onRunApbs()));
+  connect(action, &QAction::triggered, this, &Apbs::onRunApbs);
   m_actions.append(action);
 
   action = new QAction(this);
   action->setText(tr("Open Output File…"));
-  connect(action, SIGNAL(triggered()), this, SLOT(onOpenOutputFile()));
+  connect(action, &QAction::triggered, this, &Apbs::onOpenOutputFile);
   m_actions.append(action);
 }
 
@@ -72,8 +72,7 @@ void Apbs::onOpenOutputFile()
 
 void Apbs::meshGeneratorFinished()
 {
-  auto* generator =
-    qobject_cast<QtGui::MeshGenerator*>(sender());
+  auto* generator = qobject_cast<QtGui::MeshGenerator*>(sender());
   if (!generator) {
     return;
   }
@@ -155,12 +154,11 @@ bool Apbs::loadOpenDxFile(const QString& fileName, QtGui::Molecule& molecule)
       qApp->processEvents();
 
       Mesh* mesh = molecule.addMesh();
-      auto* meshGenerator =
-        new QtGui::MeshGenerator(cube, mesh, 0.1f);
-      connect(meshGenerator, SIGNAL(finished()), this,
-              SLOT(meshGeneratorFinished()));
-      connect(meshGenerator, SIGNAL(progressValueChanged(int)), this,
-              SLOT(onMeshGeneratorProgress(int)));
+      auto* meshGenerator = new QtGui::MeshGenerator(cube, mesh, 0.1f);
+      connect(meshGenerator, &QThread::finished, this,
+              &Apbs::meshGeneratorFinished);
+      connect(meshGenerator, &QtGui::MeshGenerator::progressValueChanged, this,
+              &Apbs::onMeshGeneratorProgress);
       meshGenerator->run();
 
       // generate negative mesh
@@ -171,10 +169,10 @@ bool Apbs::loadOpenDxFile(const QString& fileName, QtGui::Molecule& molecule)
 
       mesh = molecule.addMesh();
       meshGenerator = new QtGui::MeshGenerator(cube, mesh, -0.1f);
-      connect(meshGenerator, SIGNAL(finished()), this,
-              SLOT(meshGeneratorFinished()));
-      connect(meshGenerator, SIGNAL(progressValueChanged(int)), this,
-              SLOT(onMeshGeneratorProgress(int)));
+      connect(meshGenerator, &QThread::finished, this,
+              &Apbs::meshGeneratorFinished);
+      connect(meshGenerator, &QtGui::MeshGenerator::progressValueChanged, this,
+              &Apbs::onMeshGeneratorProgress);
       meshGenerator->run();
 
       m_progressDialog->setValue(100);
@@ -184,4 +182,4 @@ bool Apbs::loadOpenDxFile(const QString& fileName, QtGui::Molecule& molecule)
 
   return true;
 }
-}
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/apbs/apbsdialog.cpp b/avogadro/qtplugins/apbs/apbsdialog.cpp
index f7d74e3297..b500ecb546 100644
--- a/avogadro/qtplugins/apbs/apbsdialog.cpp
+++ b/avogadro/qtplugins/apbs/apbsdialog.cpp
@@ -31,13 +31,15 @@ ApbsDialog::ApbsDialog(QWidget* parent_)
 {
   m_ui->setupUi(this);
 
-  connect(m_ui->closeButton, SIGNAL(clicked()), this, SLOT(reject()));
-  connect(m_ui->openPdbFileButton, SIGNAL(clicked()), this,
-          SLOT(openPdbFile()));
-  connect(m_ui->openPqrFileButton, SIGNAL(clicked()), this,
-          SLOT(openPqrFile()));
-  connect(m_ui->runApbsButton, SIGNAL(clicked()), this, SLOT(runApbs()));
-  connect(m_ui->runPdb2PqrButton, SIGNAL(clicked()), this, SLOT(runPdb2Pqr()));
+  connect(m_ui->closeButton, &QAbstractButton::clicked, this, &QDialog::reject);
+  connect(m_ui->openPdbFileButton, &QAbstractButton::clicked, this,
+          &ApbsDialog::openPdbFile);
+  connect(m_ui->openPqrFileButton, &QAbstractButton::clicked, this,
+          &ApbsDialog::openPqrFile);
+  connect(m_ui->runApbsButton, &QAbstractButton::clicked, this,
+          &ApbsDialog::runApbs);
+  connect(m_ui->runPdb2PqrButton, &QAbstractButton::clicked, this,
+          &ApbsDialog::runPdb2Pqr);
   connect(m_ui->saveInputFileButton, SIGNAL(clicked()), this,
           SLOT(saveInputFile()));
 }
@@ -115,7 +117,7 @@ void ApbsDialog::runApbs()
     m_cubeFileName = "pot-PE0.dx";
 
     ApbsOutputDialog dialog(this);
-    connect(&dialog, SIGNAL(accepted()), this, SLOT(accept()));
+    connect(&dialog, &QDialog::accepted, this, &QDialog::accept);
     int code = dialog.exec();
     if (code == QDialog::Accepted) {
       m_loadStructureFile = dialog.loadStructureFile();
@@ -218,4 +220,4 @@ void ApbsDialog::updatePreviewTextImmediately()
 
   m_ui->textEdit->setText(m_inputGenerator->fileContents("apbs.in"));
 }
-}
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/applycolors/applycolors.cpp b/avogadro/qtplugins/applycolors/applycolors.cpp
index 28c5f66fd6..acafe6d6be 100644
--- a/avogadro/qtplugins/applycolors/applycolors.cpp
+++ b/avogadro/qtplugins/applycolors/applycolors.cpp
@@ -45,53 +45,55 @@ ApplyColors::ApplyColors(QObject* parent_)
 
   action = new QAction(tr("By Custom Color…"), this);
   action->setData(atomColors);
-  connect(action, SIGNAL(triggered()), SLOT(openColorDialog()));
+  connect(action, &QAction::triggered, this, &ApplyColors::openColorDialog);
   m_actions.append(action);
 
   action = new QAction(tr("By Atomic Index…"), this);
   action->setData(atomColors);
-  connect(action, SIGNAL(triggered()), SLOT(applyIndexColors()));
+  connect(action, &QAction::triggered, this, &ApplyColors::applyIndexColors);
   m_actions.append(action);
 
   action = new QAction(tr("By Distance…"), this);
   action->setData(atomColors);
-  connect(action, SIGNAL(triggered()), SLOT(applyDistanceColors()));
+  connect(action, &QAction::triggered, this, &ApplyColors::applyDistanceColors);
   m_actions.append(action);
 
   action = new QAction(tr("By Element"), this);
   action->setData(atomColors);
-  connect(action, SIGNAL(triggered()), SLOT(resetColors()));
+  connect(action, &QAction::triggered, this, &ApplyColors::resetColors);
   m_actions.append(action);
 
   // not sure if we want to color atoms by residue or not...
   action = new QAction(tr("By Custom Color…"), this);
   action->setData(residueColors);
-  connect(action, SIGNAL(triggered()), SLOT(openColorDialogResidue()));
+  connect(action, &QAction::triggered, this,
+          &ApplyColors::openColorDialogResidue);
   m_actions.append(action);
 
   action = new QAction(tr("By Chain"), this);
   action->setData(residueColors);
-  connect(action, SIGNAL(triggered()), SLOT(resetColorsResidue()));
+  connect(action, &QAction::triggered, this, &ApplyColors::resetColorsResidue);
   m_actions.append(action);
 
   action = new QAction(tr("By Partial Charge…"), this);
   action->setData(atomColors);
-  connect(action, SIGNAL(triggered()), SLOT(applyChargeColors()));
+  connect(action, &QAction::triggered, this, &ApplyColors::applyChargeColors);
   m_actions.append(action);
 
   action = new QAction(tr("By Secondary Structure"), this);
   action->setData(residueColors);
-  connect(action, SIGNAL(triggered()), SLOT(applySecondaryStructureColors()));
+  connect(action, &QAction::triggered, this,
+          &ApplyColors::applySecondaryStructureColors);
   m_actions.append(action);
 
   action = new QAction(tr("By Amino Acid"), this);
   action->setData(residueColors);
-  connect(action, SIGNAL(triggered()), SLOT(applyAminoColors()));
+  connect(action, &QAction::triggered, this, &ApplyColors::applyAminoColors);
   m_actions.append(action);
 
   action = new QAction(tr("By Shapely Scheme"), this);
   action->setData(residueColors);
-  connect(action, SIGNAL(triggered()), SLOT(applyShapelyColors()));
+  connect(action, &QAction::triggered, this, &ApplyColors::applyShapelyColors);
   m_actions.append(action);
 }
 
@@ -165,8 +167,8 @@ void ApplyColors::openColorDialog()
 {
   if (m_dialog == nullptr) {
     m_dialog = new QColorDialog(qobject_cast<QWidget*>(parent()));
-    connect(m_dialog, SIGNAL(currentColorChanged(const QColor&)),
-            SLOT(applyCustomColor(const QColor&)));
+    connect(m_dialog, &QColorDialog::currentColorChanged, this,
+            &ApplyColors::applyCustomColor);
   }
 
   m_dialog->exec();
@@ -385,8 +387,8 @@ void ApplyColors::openColorDialogResidue()
     m_dialog = new QColorDialog(qobject_cast<QWidget*>(parent()));
   }
   m_dialog->disconnect();
-  connect(m_dialog, SIGNAL(currentColorChanged(const QColor&)),
-          SLOT(applyCustomColorResidue(const QColor&)));
+  connect(m_dialog, &QColorDialog::currentColorChanged, this,
+          &ApplyColors::applyCustomColorResidue);
 
   m_dialog->exec();
 }
diff --git a/avogadro/qtplugins/bonding/bonding.cpp b/avogadro/qtplugins/bonding/bonding.cpp
index e0901f7f9d..c8d53236bd 100644
--- a/avogadro/qtplugins/bonding/bonding.cpp
+++ b/avogadro/qtplugins/bonding/bonding.cpp
@@ -42,11 +42,11 @@ Bonding::Bonding(QObject* parent_)
   m_orderAction->setProperty("menu priority", 735);
   m_clearAction->setProperty("menu priority", 720);
 
-  connect(m_action, SIGNAL(triggered()), SLOT(bond()));
-  connect(m_createBondsAction, SIGNAL(triggered()), SLOT(createBond()));
-  connect(m_orderAction, SIGNAL(triggered()), SLOT(bondOrders()));
-  connect(m_clearAction, SIGNAL(triggered()), SLOT(clearBonds()));
-  connect(m_configAction, SIGNAL(triggered()), SLOT(configure()));
+  connect(m_action, &QAction::triggered, this, &Bonding::bond);
+  connect(m_createBondsAction, &QAction::triggered, this, &Bonding::createBond);
+  connect(m_orderAction, &QAction::triggered, this, &Bonding::bondOrders);
+  connect(m_clearAction, &QAction::triggered, this, &Bonding::clearBonds);
+  connect(m_configAction, &QAction::triggered, this, &Bonding::configure);
 }
 
 QList<QAction*> Bonding::actions() const
@@ -103,8 +103,10 @@ void Bonding::configure()
     m_ui->toleranceSpinBox->setValue(m_tolerance);
     m_ui->minimumSpinBox->setValue(m_minDistance);
 
-    connect(m_ui->buttonBox, SIGNAL(accepted()), this, SLOT(setValues()));
-    connect(m_ui->buttonBox, SIGNAL(rejected()), m_dialog, SLOT(close()));
+    connect(m_ui->buttonBox, &QDialogButtonBox::accepted, this,
+            &Bonding::setValues);
+    connect(m_ui->buttonBox, &QDialogButtonBox::rejected, m_dialog,
+            &QWidget::close);
   }
 
   m_dialog->show();
diff --git a/avogadro/qtplugins/centroid/centroid.cpp b/avogadro/qtplugins/centroid/centroid.cpp
index cfd4c658e4..0e44b0f6c4 100644
--- a/avogadro/qtplugins/centroid/centroid.cpp
+++ b/avogadro/qtplugins/centroid/centroid.cpp
@@ -29,9 +29,9 @@ Centroid::Centroid(QObject* parent_)
   m_comAction->setProperty("menu priority", 180);
   m_normalAction->setProperty("menu priority", 170);
 
-  connect(m_centroidAction, SIGNAL(triggered()), SLOT(addCentroid()));
-  connect(m_comAction, SIGNAL(triggered()), SLOT(addCenterOfMass()));
-  connect(m_normalAction, SIGNAL(triggered()), SLOT(normal()));
+  connect(m_centroidAction, &QAction::triggered, this, &Centroid::addCentroid);
+  connect(m_comAction, &QAction::triggered, this, &Centroid::addCenterOfMass);
+  connect(m_normalAction, &QAction::triggered, this, &Centroid::normal);
 }
 
 QList<QAction*> Centroid::actions() const
diff --git a/avogadro/qtplugins/commandscripts/command.cpp b/avogadro/qtplugins/commandscripts/command.cpp
index 0cc58778a5..82a70f1061 100644
--- a/avogadro/qtplugins/commandscripts/command.cpp
+++ b/avogadro/qtplugins/commandscripts/command.cpp
@@ -194,8 +194,9 @@ void Command::menuActivated()
   auto* buttonBox =
     new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel);
 
-  connect(buttonBox, SIGNAL(accepted()), this, SLOT(run()));
-  connect(buttonBox, SIGNAL(rejected()), m_currentDialog, SLOT(reject()));
+  connect(buttonBox, &QDialogButtonBox::accepted, this, &Command::run);
+  connect(buttonBox, &QDialogButtonBox::rejected, m_currentDialog,
+          &QDialog::reject);
   vbox->addWidget(buttonBox);
   m_currentDialog->setLayout(vbox);
   m_currentDialog->exec();
@@ -210,8 +211,8 @@ void Command::run()
     m_progress->deleteLater();
 
   if (m_currentScript) {
-    disconnect(m_currentScript, SIGNAL(finished()), this,
-               SLOT(processFinished()));
+    disconnect(m_currentScript, &QtGui::InterfaceScript::finished, this,
+               &Command::processFinished);
     m_currentScript->deleteLater();
   }
 
@@ -223,7 +224,8 @@ void Command::run()
       m_currentInterface->interfaceScript().scriptFilePath();
 
     m_currentScript = new InterfaceScript(scriptFilePath, parent());
-    connect(m_currentScript, SIGNAL(finished()), this, SLOT(processFinished()));
+    connect(m_currentScript, &QtGui::InterfaceScript::finished, this,
+            &Command::processFinished);
 
     // no cancel button - just an indication we're waiting...
     QString title = tr("Processing %1").arg(m_currentScript->displayName());
@@ -293,8 +295,8 @@ void Command::configurePython()
   dlg.setLayout(layout);
 
   // Connect
-  connect(buttonBox, SIGNAL(accepted()), &dlg, SLOT(accept()));
-  connect(buttonBox, SIGNAL(rejected()), &dlg, SLOT(reject()));
+  connect(buttonBox, &QDialogButtonBox::accepted, &dlg, &QDialog::accept);
+  connect(buttonBox, &QDialogButtonBox::rejected, &dlg, &QDialog::reject);
 
   // Show dialog
   auto response = static_cast<QDialog::DialogCode>(dlg.exec());
@@ -337,7 +339,7 @@ void Command::addAction(const QString& label, const QString& scriptFilePath)
   auto* action = new QAction(tr(label.toUtf8()), this);
   action->setData(scriptFilePath);
   action->setEnabled(true);
-  connect(action, SIGNAL(triggered()), SLOT(menuActivated()));
+  connect(action, &QAction::triggered, this, &Command::menuActivated);
   m_actions << action;
 }
 
diff --git a/avogadro/qtplugins/configurepython/configurepython.cpp b/avogadro/qtplugins/configurepython/configurepython.cpp
index 4906d0db6b..755567de54 100644
--- a/avogadro/qtplugins/configurepython/configurepython.cpp
+++ b/avogadro/qtplugins/configurepython/configurepython.cpp
@@ -31,7 +31,7 @@ ConfigurePython::ConfigurePython(QObject* parent_)
   m_action->setEnabled(true);
   m_action->setText(tr("Python Settings…"));
   m_action->setProperty("menu priority", 510);
-  connect(m_action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(m_action, &QAction::triggered, this, &ConfigurePython::showDialog);
 
   // check for Python on first launch
   QStringList paths = pythonPaths();
diff --git a/avogadro/qtplugins/coordinateeditor/coordinateeditor.cpp b/avogadro/qtplugins/coordinateeditor/coordinateeditor.cpp
index fd7b789b7a..d9c43b59bb 100644
--- a/avogadro/qtplugins/coordinateeditor/coordinateeditor.cpp
+++ b/avogadro/qtplugins/coordinateeditor/coordinateeditor.cpp
@@ -17,12 +17,10 @@ CoordinateEditor::CoordinateEditor(QObject* parent_)
     m_action(new QAction(tr("Atomic &Coordinate Editor…"), this))
 {
   m_action->setProperty("menu priority", 900);
-  connect(m_action, SIGNAL(triggered()), SLOT(triggered()));
+  connect(m_action, &QAction::triggered, this, &CoordinateEditor::triggered);
 }
 
-CoordinateEditor::~CoordinateEditor()
-{
-}
+CoordinateEditor::~CoordinateEditor() {}
 
 QList<QAction*> CoordinateEditor::actions() const
 {
@@ -46,7 +44,8 @@ void CoordinateEditor::triggered()
   if (!m_dialog) {
     m_dialog = new CoordinateEditorDialog(qobject_cast<QWidget*>(parent()));
     m_dialog->setMolecule(m_molecule);
-    connect(m_dialog, SIGNAL(pastedMolecule()), SLOT(pastedMolecule()));
+    connect(m_dialog, &CoordinateEditorDialog::pastedMolecule, this,
+            &CoordinateEditor::pastedMolecule);
   }
 
   m_dialog->show();
@@ -59,4 +58,4 @@ void CoordinateEditor::pastedMolecule()
   requestActiveTool("Navigator");
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/coordinateeditor/coordinateeditordialog.cpp b/avogadro/qtplugins/coordinateeditor/coordinateeditordialog.cpp
index 6f9c21f508..e8cb6592be 100644
--- a/avogadro/qtplugins/coordinateeditor/coordinateeditordialog.cpp
+++ b/avogadro/qtplugins/coordinateeditor/coordinateeditordialog.cpp
@@ -140,8 +140,8 @@ CoordinateEditorDialog::CoordinateEditorDialog(QWidget* parent_)
 
   // Set up text editor
   m_ui->text->setFont(QFont(EDITOR_FONT, qApp->font().pointSize()));
-  connect(m_ui->text->document(), SIGNAL(modificationChanged(bool)),
-          SLOT(textModified(bool)));
+  connect(m_ui->text->document(), &QTextDocument::modificationChanged, this,
+          &CoordinateEditorDialog::textModified);
 
   // Setup spec edit
   QRegularExpression specRegExp("[#ZGSLNabcxyz01_]*");
@@ -149,19 +149,28 @@ CoordinateEditorDialog::CoordinateEditorDialog(QWidget* parent_)
   m_ui->spec->setValidator(specValidator);
   connect(m_ui->presets, SIGNAL(currentIndexChanged(int)),
           SLOT(presetChanged(int)));
-  connect(m_ui->spec, SIGNAL(textChanged(QString)), SLOT(specChanged()));
-  connect(m_ui->spec, SIGNAL(textEdited(QString)), SLOT(specEdited()));
+  connect(m_ui->spec, &QLineEdit::textChanged, this,
+          &CoordinateEditorDialog::specChanged);
+  connect(m_ui->spec, &QLineEdit::textEdited, this,
+          &CoordinateEditorDialog::specEdited);
 
   connect(m_ui->distanceUnit, SIGNAL(currentIndexChanged(int)),
           SLOT(updateText()));
 
-  connect(m_ui->help, SIGNAL(clicked()), SLOT(helpClicked()));
-  connect(m_ui->cut, SIGNAL(clicked()), SLOT(cutClicked()));
-  connect(m_ui->copy, SIGNAL(clicked()), SLOT(copyClicked()));
-  connect(m_ui->paste, SIGNAL(clicked()), SLOT(pasteClicked()));
-  connect(m_ui->revert, SIGNAL(clicked()), SLOT(revertClicked()));
-  connect(m_ui->clear, SIGNAL(clicked()), SLOT(clearClicked()));
-  connect(m_ui->apply, SIGNAL(clicked()), SLOT(applyClicked()));
+  connect(m_ui->help, &QAbstractButton::clicked, this,
+          &CoordinateEditorDialog::helpClicked);
+  connect(m_ui->cut, &QAbstractButton::clicked, this,
+          &CoordinateEditorDialog::cutClicked);
+  connect(m_ui->copy, &QAbstractButton::clicked, this,
+          &CoordinateEditorDialog::copyClicked);
+  connect(m_ui->paste, &QAbstractButton::clicked, this,
+          &CoordinateEditorDialog::pasteClicked);
+  connect(m_ui->revert, &QAbstractButton::clicked, this,
+          &CoordinateEditorDialog::revertClicked);
+  connect(m_ui->clear, &QAbstractButton::clicked, this,
+          &CoordinateEditorDialog::clearClicked);
+  connect(m_ui->apply, &QAbstractButton::clicked, this,
+          &CoordinateEditorDialog::applyClicked);
 
   m_ui->cut->setIcon(QIcon::fromTheme("edit-cut"));
   m_ui->copy->setIcon(QIcon::fromTheme("edit-copy"));
@@ -182,7 +191,8 @@ void CoordinateEditorDialog::setMolecule(QtGui::Molecule* mol)
     if (m_molecule)
       m_molecule->disconnect(this);
     m_molecule = mol;
-    connect(m_molecule, SIGNAL(changed(uint)), SLOT(moleculeChanged(uint)));
+    connect(m_molecule, &QtGui::Molecule::changed, this,
+            &CoordinateEditorDialog::moleculeChanged);
     updateText();
   }
 }
@@ -528,7 +538,7 @@ void CoordinateEditorDialog::validateInputWorker()
 
   // If we're not at the end, post this method back into the event loop.
   if (!lineCursor.atEnd()) {
-    QTimer::singleShot(0, this, SLOT(validateInputWorker()));
+    QTimer::singleShot(0, this, &CoordinateEditorDialog::validateInputWorker);
   } else {
     // Otherwise emit the finished signal.
     emit validationFinished(!m_ui->text->hasInvalidMarks());
@@ -567,7 +577,8 @@ void CoordinateEditorDialog::applyClicked()
       break;
   }
 
-  connect(this, SIGNAL(validationFinished(bool)), SLOT(applyFinish(bool)));
+  connect(this, &CoordinateEditorDialog::validationFinished, this,
+          &CoordinateEditorDialog::applyFinish);
   validateInput();
 }
 
@@ -577,8 +588,8 @@ void CoordinateEditorDialog::applyFinish(bool valid)
   m_validate->collectAtoms = false;
   QVector<AtomStruct> atoms(m_validate->atoms);
   m_validate->atoms.clear();
-  disconnect(this, SIGNAL(validationFinished(bool)), this,
-             SLOT(applyFinish(bool)));
+  disconnect(this, &CoordinateEditorDialog::validationFinished, this,
+             &CoordinateEditorDialog::applyFinish);
 
   if (!valid) {
     QMessageBox::critical(this, tr("Error applying geometry"),
@@ -654,9 +665,11 @@ void CoordinateEditorDialog::buildPresets()
 void CoordinateEditorDialog::listenForTextEditChanges(bool enable)
 {
   if (enable)
-    connect(m_ui->text, SIGNAL(textChanged()), this, SLOT(validateInput()));
+    connect(m_ui->text, &QTextEdit::textChanged, this,
+            &CoordinateEditorDialog::validateInput);
   else
-    disconnect(m_ui->text, SIGNAL(textChanged()), this, SLOT(validateInput()));
+    disconnect(m_ui->text, &QTextEdit::textChanged, this,
+               &CoordinateEditorDialog::validateInput);
 }
 
 QString CoordinateEditorDialog::detectInputFormat() const
diff --git a/avogadro/qtplugins/copypaste/copypaste.cpp b/avogadro/qtplugins/copypaste/copypaste.cpp
index 6b17ff1adc..f5f77c7489 100644
--- a/avogadro/qtplugins/copypaste/copypaste.cpp
+++ b/avogadro/qtplugins/copypaste/copypaste.cpp
@@ -37,28 +37,28 @@ CopyPaste::CopyPaste(QObject* parent_)
   m_cutAction->setShortcut(QKeySequence::Cut);
   m_cutAction->setIcon(QIcon::fromTheme("edit-cut"));
   m_cutAction->setProperty("menu priority", 560);
-  connect(m_cutAction, SIGNAL(triggered()), SLOT(cut()));
+  connect(m_cutAction, &QAction::triggered, this, &CopyPaste::cut);
 
   m_copyAction->setShortcut(QKeySequence::Copy);
   m_copyAction->setIcon(QIcon::fromTheme("edit-copy"));
   m_copyAction->setProperty("menu priority", 550);
-  connect(m_copyAction, SIGNAL(triggered()), SLOT(copyCJSON()));
+  connect(m_copyAction, &QAction::triggered, this, &CopyPaste::copyCJSON);
 
   m_copySMILES->setProperty("menu priority", 540);
-  connect(m_copySMILES, SIGNAL(triggered()), SLOT(copySMILES()));
+  connect(m_copySMILES, &QAction::triggered, this, &CopyPaste::copySMILES);
 
   m_copyInChI->setProperty("menu priority", 530);
-  connect(m_copyInChI, SIGNAL(triggered()), SLOT(copyInChI()));
+  connect(m_copyInChI, &QAction::triggered, this, &CopyPaste::copyInChI);
 
   m_pasteAction->setShortcut(QKeySequence::Paste);
   m_pasteAction->setIcon(QIcon::fromTheme("edit-paste"));
   m_pasteAction->setProperty("menu priority", 510);
-  connect(m_pasteAction, SIGNAL(triggered()), SLOT(paste()));
+  connect(m_pasteAction, &QAction::triggered, this, &CopyPaste::paste);
 
   m_clearAction->setShortcut(QKeySequence::Delete);
   m_clearAction->setIcon(QIcon::fromTheme("edit-clear"));
   m_clearAction->setProperty("menu priority", 500);
-  connect(m_clearAction, SIGNAL(triggered()), SLOT(clear()));
+  connect(m_clearAction, &QAction::triggered, this, &CopyPaste::clear);
 }
 
 CopyPaste::~CopyPaste()
diff --git a/avogadro/qtplugins/cp2kinput/cp2kinput.cpp b/avogadro/qtplugins/cp2kinput/cp2kinput.cpp
index ee0d8afcd8..c39c80d717 100644
--- a/avogadro/qtplugins/cp2kinput/cp2kinput.cpp
+++ b/avogadro/qtplugins/cp2kinput/cp2kinput.cpp
@@ -13,8 +13,8 @@
 
 #include <avogadro/molequeue/client/jobobject.h>
 
-#include <QtCore/QDebug>
 #include <QAction>
+#include <QtCore/QDebug>
 #include <QtWidgets/QMessageBox>
 
 namespace Avogadro {
@@ -31,7 +31,7 @@ Cp2kInput::Cp2kInput(QObject* parent_)
 {
   m_action->setEnabled(true);
   m_action->setText(tr("&CP2K…"));
-  connect(m_action, SIGNAL(triggered()), SLOT(menuActivated()));
+  connect(m_action, &QAction::triggered, this, &Cp2kInput::menuActivated);
 }
 
 Cp2kInput::~Cp2kInput() {}
@@ -98,8 +98,8 @@ void Cp2kInput::menuActivated()
 {
   if (!m_dialog) {
     m_dialog = new Cp2kInputDialog(qobject_cast<QWidget*>(parent()));
-    connect(m_dialog, SIGNAL(openJobOutput(Avogadro::MoleQueue::JobObject)), this,
-            SLOT(openJobOutput(Avogadro::MoleQueue::JobObject)));
+    connect(m_dialog, &Cp2kInputDialog::openJobOutput, this,
+            &Cp2kInput::openJobOutput);
   }
   m_dialog->setMolecule(m_molecule);
   m_dialog->show();
diff --git a/avogadro/qtplugins/cp2kinput/cp2kinputdialog.cpp b/avogadro/qtplugins/cp2kinput/cp2kinputdialog.cpp
index 5eec8b6ddf..1be7f6078d 100644
--- a/avogadro/qtplugins/cp2kinput/cp2kinputdialog.cpp
+++ b/avogadro/qtplugins/cp2kinput/cp2kinputdialog.cpp
@@ -31,9 +31,9 @@
 #include <map>
 #include <vector>
 
+using Avogadro::MoleQueue::JobObject;
 using Avogadro::MoleQueue::MoleQueueDialog;
 using Avogadro::MoleQueue::MoleQueueManager;
-using Avogadro::MoleQueue::JobObject;
 
 namespace Avogadro::QtPlugins {
 
@@ -145,8 +145,10 @@ void Cp2kInputDialog::setMolecule(QtGui::Molecule* mol)
 
   m_molecule = mol;
 
-  connect(mol, SIGNAL(changed(unsigned int)), SLOT(updatePreviewText()));
-  connect(mol, SIGNAL(changed(unsigned int)), SLOT(updateTitlePlaceholder()));
+  connect(mol, &QtGui::Molecule::changed, this,
+          &Cp2kInputDialog::updatePreviewText);
+  connect(mol, &QtGui::Molecule::changed, this,
+          &Cp2kInputDialog::updateTitlePlaceholder);
 
   updateTitlePlaceholder();
   updatePreviewText();
@@ -159,13 +161,13 @@ void Cp2kInputDialog::showEvent(QShowEvent* e)
   // Update the preview text if an update was requested while hidden. Use a
   // single shot to allow the dialog to show before popping up any warnings.
   if (m_updatePending)
-    QTimer::singleShot(0, this, SLOT(updatePreviewText()));
+    QTimer::singleShot(0, this, &Cp2kInputDialog::updatePreviewText);
 }
 
 void Cp2kInputDialog::connectBasic()
 {
-  connect(ui.titleEdit, SIGNAL(textChanged(QString)), this,
-          SLOT(updatePreviewText()));
+  connect(ui.titleEdit, &QLineEdit::textChanged, this,
+          &Cp2kInputDialog::updatePreviewText);
   connect(ui.calculateCombo, SIGNAL(currentIndexChanged(int)), this,
           SLOT(updatePreviewText()));
   connect(ui.calculateCombo, SIGNAL(currentIndexChanged(int)), this,
@@ -190,8 +192,8 @@ void Cp2kInputDialog::connectBasic()
           SLOT(updatePreviewText()));
   connect(ui.ewaldgmaxSpin, SIGNAL(valueChanged(double)), this,
           SLOT(updatePreviewText()));
-  connect(ui.lsdcheckBox, SIGNAL(stateChanged(bool)), this,
-          SLOT(updatePreviewText()));
+  connect(ui.lsdcheckBox, &QCheckBox::stateChanged, this,
+          &Cp2kInputDialog::updatePreviewText);
   connect(ui.maxscfspinBox, SIGNAL(valueChanged(int)), this,
           SLOT(updatePreviewText()));
   connect(ui.epsscfSpinBox, SIGNAL(valueChanged(double)), this,
@@ -210,11 +212,15 @@ void Cp2kInputDialog::connectPreview() {}
 
 void Cp2kInputDialog::connectButtons()
 {
-  connect(ui.resetAllButton, SIGNAL(clicked()), SLOT(resetClicked()));
-  connect(ui.defaultsButton, SIGNAL(clicked()), SLOT(defaultsClicked()));
-  connect(ui.generateButton, SIGNAL(clicked()), SLOT(generateClicked()));
-  connect(ui.computeButton, SIGNAL(clicked()), SLOT(computeClicked()));
-  connect(ui.closeButton, SIGNAL(clicked()), SLOT(close()));
+  connect(ui.resetAllButton, &QAbstractButton::clicked, this,
+          &Cp2kInputDialog::resetClicked);
+  connect(ui.defaultsButton, &QAbstractButton::clicked, this,
+          &Cp2kInputDialog::defaultsClicked);
+  connect(ui.generateButton, &QAbstractButton::clicked, this,
+          &Cp2kInputDialog::generateClicked);
+  connect(ui.computeButton, &QAbstractButton::clicked, this,
+          &Cp2kInputDialog::computeClicked);
+  connect(ui.closeButton, &QAbstractButton::clicked, this, &QWidget::close);
 }
 
 void Cp2kInputDialog::buildOptions()
@@ -553,8 +559,7 @@ void Cp2kInputDialog::updatePreviewText()
   auto functional(
     static_cast<FunctionalOption>(ui.functionalCombo->currentIndex()));
   auto basis(static_cast<BasisOption>(ui.basisCombo->currentIndex()));
-  auto method(
-    static_cast<MethodOption>(ui.methodCombo->currentIndex()));
+  auto method(static_cast<MethodOption>(ui.methodCombo->currentIndex()));
   auto EWALDType(
     static_cast<EWALDTypeOption>(ui.ewaldtypeCombo->currentIndex()));
   auto SCFGuess(
@@ -1038,4 +1043,4 @@ void Cp2kInputDialog::updateTitlePlaceholder()
   ui.titleEdit->setPlaceholderText(generateJobTitle());
 }
 
-} // end namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/crystal/crystal.cpp b/avogadro/qtplugins/crystal/crystal.cpp
index 6ecd3db438..aafbfea97c 100644
--- a/avogadro/qtplugins/crystal/crystal.cpp
+++ b/avogadro/qtplugins/crystal/crystal.cpp
@@ -38,46 +38,51 @@ Crystal::Crystal(QObject* parent_)
     m_wrapAtomsToCellAction(new QAction(this))
 {
   m_importCrystalClipboardAction->setText(tr("Import Crystal from Clipboard…"));
-  connect(m_importCrystalClipboardAction, SIGNAL(triggered()),
-          SLOT(importCrystalClipboard()));
+  connect(m_importCrystalClipboardAction, &QAction::triggered, this,
+          &Crystal::importCrystalClipboard);
   m_actions.push_back(m_importCrystalClipboardAction);
   m_importCrystalClipboardAction->setProperty("menu priority", 220);
 
   // this will be changed when the molecule is set:
   m_toggleUnitCellAction->setText(tr("Toggle Unit Cell"));
-  connect(m_toggleUnitCellAction, SIGNAL(triggered()), SLOT(toggleUnitCell()));
+  connect(m_toggleUnitCellAction, &QAction::triggered, this,
+          &Crystal::toggleUnitCell);
   m_actions.push_back(m_toggleUnitCellAction);
   m_toggleUnitCellAction->setProperty("menu priority", 210);
 
   m_editUnitCellAction->setText(tr("Edit Unit Cell…"));
-  connect(m_editUnitCellAction, SIGNAL(triggered()), SLOT(editUnitCell()));
+  connect(m_editUnitCellAction, &QAction::triggered, this,
+          &Crystal::editUnitCell);
   m_actions.push_back(m_editUnitCellAction);
   m_editUnitCellAction->setProperty("menu priority", 190);
 
   m_wrapAtomsToCellAction->setText(tr("&Wrap Atoms to Unit Cell"));
-  connect(m_wrapAtomsToCellAction, SIGNAL(triggered()),
-          SLOT(wrapAtomsToCell()));
+  connect(m_wrapAtomsToCellAction, &QAction::triggered, this,
+          &Crystal::wrapAtomsToCell);
   m_actions.push_back(m_wrapAtomsToCellAction);
   m_wrapAtomsToCellAction->setProperty("menu priority", 180);
 
   m_standardOrientationAction->setText(tr("Rotate to Standard &Orientation"));
-  connect(m_standardOrientationAction, SIGNAL(triggered()),
-          SLOT(standardOrientation()));
+  connect(m_standardOrientationAction, &QAction::triggered, this,
+          &Crystal::standardOrientation);
   m_actions.push_back(m_standardOrientationAction);
   m_standardOrientationAction->setProperty("menu priority", 170);
 
   m_scaleVolumeAction->setText(tr("Scale Cell &Volume…"));
-  connect(m_scaleVolumeAction, SIGNAL(triggered()), SLOT(scaleVolume()));
+  connect(m_scaleVolumeAction, &QAction::triggered, this,
+          &Crystal::scaleVolume);
   m_actions.push_back(m_scaleVolumeAction);
   m_scaleVolumeAction->setProperty("menu priority", 160);
 
   m_buildSupercellAction->setText(tr("Build &Supercell…"));
-  connect(m_buildSupercellAction, SIGNAL(triggered()), SLOT(buildSupercell()));
+  connect(m_buildSupercellAction, &QAction::triggered, this,
+          &Crystal::buildSupercell);
   m_actions.push_back(m_buildSupercellAction);
   m_buildSupercellAction->setProperty("menu priority", 150);
 
   m_niggliReduceAction->setText(tr("Reduce Cell (&Niggli)"));
-  connect(m_niggliReduceAction, SIGNAL(triggered()), SLOT(niggliReduce()));
+  connect(m_niggliReduceAction, &QAction::triggered, this,
+          &Crystal::niggliReduce);
   m_actions.push_back(m_niggliReduceAction);
   m_niggliReduceAction->setProperty("menu priority", 140);
 
@@ -116,7 +121,8 @@ void Crystal::setMolecule(QtGui::Molecule* mol)
     m_unitCellDialog->setMolecule(m_molecule);
 
   if (m_molecule)
-    connect(m_molecule, SIGNAL(changed(uint)), SLOT(moleculeChanged(uint)));
+    connect(m_molecule, &QtGui::Molecule::changed, this,
+            &Crystal::moleculeChanged);
 
   updateActions();
 }
diff --git a/avogadro/qtplugins/crystal/crystalscene.cpp b/avogadro/qtplugins/crystal/crystalscene.cpp
index 4c9530f5c1..8c9ca62c17 100644
--- a/avogadro/qtplugins/crystal/crystalscene.cpp
+++ b/avogadro/qtplugins/crystal/crystalscene.cpp
@@ -176,11 +176,12 @@ QWidget* CrystalScene::setupWidget()
     auto* multiColor = new QCheckBox;
     multiColor->setChecked(m_multiColor);
     form->addRow(tr("Color axes:"), multiColor);
-    connect(multiColor, SIGNAL(toggled(bool)), SLOT(setMultiColor(bool)));
+    connect(multiColor, &QAbstractButton::toggled, this,
+            &CrystalScene::setMultiColor);
 
     auto* color = new QtGui::ColorButton;
-    connect(color, SIGNAL(colorChanged(const QColor&)),
-            SLOT(setColor(const QColor&)));
+    connect(color, &QtGui::ColorButton::colorChanged, this,
+            &CrystalScene::setColor);
     form->addRow(tr("Line color:"), color);
 
     v->addLayout(form);
diff --git a/avogadro/qtplugins/crystal/unitcelldialog.cpp b/avogadro/qtplugins/crystal/unitcelldialog.cpp
index 6c55053d14..787b228d6c 100644
--- a/avogadro/qtplugins/crystal/unitcelldialog.cpp
+++ b/avogadro/qtplugins/crystal/unitcelldialog.cpp
@@ -27,7 +27,7 @@ const char MATRIX_FMT = 'f';
 // Valid value separators in matrix editors:
 const static QRegularExpression MATRIX_SEP(
   R"(\s|,|;|\||\[|\]|\{|\}|\(|\)|\&|/|<|>)");
-}
+} // namespace
 
 namespace Avogadro::QtPlugins {
 
@@ -44,13 +44,15 @@ UnitCellDialog::UnitCellDialog(QWidget* p)
   connect(m_ui->beta, SIGNAL(valueChanged(double)), SLOT(parametersEdited()));
   connect(m_ui->gamma, SIGNAL(valueChanged(double)), SLOT(parametersEdited()));
 
-  connect(m_ui->cellMatrix, SIGNAL(textChanged()), SLOT(cellMatrixEdited()));
+  connect(m_ui->cellMatrix, &QPlainTextEdit::textChanged, this,
+          &UnitCellDialog::cellMatrixEdited);
 
-  connect(m_ui->fractionalMatrix, SIGNAL(textChanged()),
-          SLOT(fractionalMatrixEdited()));
+  connect(m_ui->fractionalMatrix, &QPlainTextEdit::textChanged, this,
+          &UnitCellDialog::fractionalMatrixEdited);
 
-  connect(m_ui->apply, SIGNAL(clicked()), SLOT(apply()));
-  connect(m_ui->revert, SIGNAL(clicked()), SLOT(revert()));
+  connect(m_ui->apply, &QAbstractButton::clicked, this, &UnitCellDialog::apply);
+  connect(m_ui->revert, &QAbstractButton::clicked, this,
+          &UnitCellDialog::revert);
 }
 
 UnitCellDialog::~UnitCellDialog()
@@ -67,7 +69,8 @@ void UnitCellDialog::setMolecule(QtGui::Molecule* molecule)
     m_molecule = molecule;
 
     if (m_molecule)
-      connect(m_molecule, SIGNAL(changed(uint)), SLOT(moleculeChanged(uint)));
+      connect(m_molecule, &QtGui::Molecule::changed, this,
+              &UnitCellDialog::moleculeChanged);
 
     revert();
   }
@@ -366,4 +369,4 @@ Matrix3 UnitCellDialog::stringToMatrix(const QString& str)
   return result;
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/customelements/customelements.cpp b/avogadro/qtplugins/customelements/customelements.cpp
index 08b0222421..d1f0f1c26d 100644
--- a/avogadro/qtplugins/customelements/customelements.cpp
+++ b/avogadro/qtplugins/customelements/customelements.cpp
@@ -18,14 +18,13 @@ CustomElements::CustomElements(QObject* parent_)
   : Avogadro::QtGui::ExtensionPlugin(parent_), m_molecule(nullptr),
     m_reassignAction(new QAction(tr("Reassign &Custom Elements…"), this))
 {
-  connect(m_reassignAction, SIGNAL(triggered()), SLOT(reassign()));
+  connect(m_reassignAction, &QAction::triggered, this,
+          &CustomElements::reassign);
 
   updateReassignAction();
 }
 
-CustomElements::~CustomElements()
-{
-}
+CustomElements::~CustomElements() {}
 
 QString CustomElements::description() const
 {
@@ -51,7 +50,8 @@ void CustomElements::setMolecule(QtGui::Molecule* mol)
     m_molecule = mol;
 
     if (m_molecule)
-      connect(m_molecule, SIGNAL(changed(uint)), SLOT(moleculeChanged(uint)));
+      connect(m_molecule, &QtGui::Molecule::changed, this,
+              &CustomElements::moleculeChanged);
 
     updateReassignAction();
   }
@@ -79,4 +79,4 @@ void CustomElements::updateReassignAction()
   m_reassignAction->setEnabled(m_molecule && m_molecule->hasCustomElements());
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/dipole/dipole.cpp b/avogadro/qtplugins/dipole/dipole.cpp
index 515a85c955..7690e315e1 100644
--- a/avogadro/qtplugins/dipole/dipole.cpp
+++ b/avogadro/qtplugins/dipole/dipole.cpp
@@ -36,7 +36,7 @@ void Dipole::process(const QtGui::Molecule& molecule,
 {
   // check if the molecule is empty
   // (single atoms don't have a dipole moment)
-  if (molecule.atomCount() < 0)
+  if (molecule.atomCount() < 2)
     return;
 
   // check if the molecule has the dipole set
@@ -46,7 +46,8 @@ void Dipole::process(const QtGui::Molecule& molecule,
     } else {
       // connect to molecule changes
       connect(&molecule, &QtGui::Molecule::update, this, &Dipole::updateDipole);
-      connect(&molecule, SIGNAL(changed(unsigned int)), SLOT(updateDipole()));
+      connect(&molecule, &QtGui::Molecule::changed, this,
+              &Dipole::updateDipole);
     }
   } else {
     // custom dipole moment set
@@ -89,7 +90,7 @@ void Dipole::updateDipole()
     m_dipoleVector =
       Calc::ChargeManager::instance().dipoleMoment(m_type, *molecule);
     // single-shot
-    QTimer::singleShot(0, this, SLOT(updateFinished()));
+    QTimer::singleShot(0, this, &Dipole::updateFinished);
   }
 }
 
diff --git a/avogadro/qtplugins/editor/editor.cpp b/avogadro/qtplugins/editor/editor.cpp
index f76eae113b..3c97df00fb 100644
--- a/avogadro/qtplugins/editor/editor.cpp
+++ b/avogadro/qtplugins/editor/editor.cpp
@@ -204,7 +204,7 @@ QUndoCommand* Editor::keyPressEvent(QKeyEvent* e)
   }
   // Set a timer to clear the buffer on first keypress:
   if (m_keyPressBuffer.isEmpty())
-    QTimer::singleShot(2000, this, SLOT(clearKeyPressBuffer()));
+    QTimer::singleShot(2000, this, &Editor::clearKeyPressBuffer);
 
   m_keyPressBuffer.append(m_keyPressBuffer.isEmpty() ? e->text().toUpper()
                                                      : e->text().toLower());
diff --git a/avogadro/qtplugins/editor/editortoolwidget.cpp b/avogadro/qtplugins/editor/editortoolwidget.cpp
index 73c81796af..24bb0b711c 100644
--- a/avogadro/qtplugins/editor/editortoolwidget.cpp
+++ b/avogadro/qtplugins/editor/editortoolwidget.cpp
@@ -91,8 +91,8 @@ void EditorToolWidget::elementChanged(int index)
     if (itemData.toInt() == ELEMENT_SELECTOR_TAG) {
       if (!m_elementSelector) {
         m_elementSelector = new QtGui::PeriodicTableView(this);
-        connect(m_elementSelector, SIGNAL(elementChanged(int)), this,
-                SLOT(elementSelectedFromTable(int)));
+        connect(m_elementSelector, &QtGui::PeriodicTableView::elementChanged,
+                this, &EditorToolWidget::elementSelectedFromTable);
       }
       m_elementSelector->setElement(m_currentElement);
       m_elementSelector->show();
@@ -121,9 +121,10 @@ void EditorToolWidget::updateElementCombo()
   // Clear and repopulate combo
   m_ui->element->clear();
   foreach (unsigned char atomicNum, allElements) {
-    m_ui->element->addItem(
-      QString("%1 (%2)").arg(QtGui::ElementTranslator::name(atomicNum)).arg(atomicNum),
-      atomicNum);
+    m_ui->element->addItem(QString("%1 (%2)")
+                             .arg(QtGui::ElementTranslator::name(atomicNum))
+                             .arg(atomicNum),
+                           atomicNum);
   }
   m_ui->element->insertSeparator(m_ui->element->count());
   m_ui->element->addItem(tr("Other…"), ELEMENT_SELECTOR_TAG);
@@ -220,4 +221,4 @@ void EditorToolWidget::saveElements()
   QSettings().setValue("editortool/userElements", atomicNums);
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/fetchpdb/fetchpdb.cpp b/avogadro/qtplugins/fetchpdb/fetchpdb.cpp
index 8b43c92e17..3e9eaf763b 100644
--- a/avogadro/qtplugins/fetchpdb/fetchpdb.cpp
+++ b/avogadro/qtplugins/fetchpdb/fetchpdb.cpp
@@ -26,7 +26,7 @@ FetchPDB::FetchPDB(QObject* parent_)
   m_action->setEnabled(true);
   m_action->setText("Fetch from &PDB…");
   m_action->setProperty("menu priority", 180);
-  connect(m_action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(m_action, &QAction::triggered, this, &FetchPDB::showDialog);
 }
 
 FetchPDB::~FetchPDB() {}
@@ -93,8 +93,8 @@ void FetchPDB::showDialog()
 
   if (!m_network) {
     m_network = new QNetworkAccessManager(this);
-    connect(m_network, SIGNAL(finished(QNetworkReply*)), this,
-            SLOT(replyFinished(QNetworkReply*)));
+    connect(m_network, &QNetworkAccessManager::finished, this,
+            &FetchPDB::replyFinished);
   }
 
   // Hard coding the PDB download URL
diff --git a/avogadro/qtplugins/focus/focus.cpp b/avogadro/qtplugins/focus/focus.cpp
index 3a8e3b59f1..b06d0703c7 100644
--- a/avogadro/qtplugins/focus/focus.cpp
+++ b/avogadro/qtplugins/focus/focus.cpp
@@ -25,8 +25,9 @@ Focus::Focus(QObject* parent_)
   m_focusSelectionAction->setProperty("menu priority", 200);
   m_unfocusAction->setProperty("menu priority", 200);
 
-  connect(m_focusSelectionAction, SIGNAL(triggered()), SLOT(focusSelection()));
-  connect(m_unfocusAction, SIGNAL(triggered()), SLOT(unfocus()));
+  connect(m_focusSelectionAction, &QAction::triggered, this,
+          &Focus::focusSelection);
+  connect(m_unfocusAction, &QAction::triggered, this, &Focus::unfocus);
 }
 
 Focus::~Focus() {}
@@ -86,7 +87,7 @@ void Focus::focusSelection()
     return;
   if (m_molecule->isSelectionEmpty())
     return;
-  
+
   Eigen::Vector3f selectionCenter(0, 0, 0);
   std::vector<Index> selection;
   for (Index i = 0; i < m_molecule->atomCount(); ++i) {
@@ -101,9 +102,9 @@ void Focus::focusSelection()
     Eigen::Vector3f pos = m_molecule->atomPosition3d(i).cast<float>();
     float distance = (pos - selectionCenter).norm();
     if (distance > selectionRadius)
-        selectionRadius = distance;
+      selectionRadius = distance;
   }
-  
+
   newFocus(selectionCenter, selectionRadius + 10.0f);
   emit updateRequested();
 }
@@ -112,9 +113,9 @@ void Focus::unfocus()
 {
   if (!m_camera || !m_scene)
     return;
-  
+
   newFocus(m_scene->center(), 2.22f * m_scene->radius());
   emit updateRequested();
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/forcefield/forcefield.cpp b/avogadro/qtplugins/forcefield/forcefield.cpp
index ce779507ae..cdade3c035 100644
--- a/avogadro/qtplugins/forcefield/forcefield.cpp
+++ b/avogadro/qtplugins/forcefield/forcefield.cpp
@@ -72,7 +72,7 @@ Forcefield::Forcefield(QObject* parent_)
   action->setShortcut(QKeySequence("Ctrl+Alt+O"));
   action->setData(optimizeAction);
   action->setProperty("menu priority", 920);
-  connect(action, SIGNAL(triggered()), SLOT(optimize()));
+  connect(action, &QAction::triggered, this, &Forcefield::optimize);
   m_actions.push_back(action);
 
   action = new QAction(this);
@@ -80,7 +80,7 @@ Forcefield::Forcefield(QObject* parent_)
   action->setText(tr("Energy")); // calculate energy
   action->setData(energyAction);
   action->setProperty("menu priority", 910);
-  connect(action, SIGNAL(triggered()), SLOT(energy()));
+  connect(action, &QAction::triggered, this, &Forcefield::energy);
   m_actions.push_back(action);
 
   action = new QAction(this);
@@ -88,7 +88,7 @@ Forcefield::Forcefield(QObject* parent_)
   action->setText(tr("Forces")); // calculate gradients
   action->setData(forcesAction);
   action->setProperty("menu priority", 910);
-  connect(action, SIGNAL(triggered()), SLOT(forces()));
+  connect(action, &QAction::triggered, this, &Forcefield::forces);
   m_actions.push_back(action);
 
   action = new QAction(this);
@@ -96,7 +96,7 @@ Forcefield::Forcefield(QObject* parent_)
   action->setText(tr("Configure…"));
   action->setData(configureAction);
   action->setProperty("menu priority", 900);
-  connect(action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(action, &QAction::triggered, this, &Forcefield::showDialog);
   m_actions.push_back(action);
 
   action = new QAction(this);
@@ -107,14 +107,14 @@ Forcefield::Forcefield(QObject* parent_)
   action->setEnabled(true);
   action->setText(tr("Freeze Selected Atoms"));
   action->setData(freezeAction);
-  connect(action, SIGNAL(triggered()), SLOT(freezeSelected()));
+  connect(action, &QAction::triggered, this, &Forcefield::freezeSelected);
   m_actions.push_back(action);
 
   action = new QAction(this);
   action->setEnabled(true);
   action->setText(tr("Unfreeze Selected Atoms"));
   action->setData(unfreezeAction);
-  connect(action, SIGNAL(triggered()), SLOT(unfreezeSelected()));
+  connect(action, &QAction::triggered, this, &Forcefield::unfreezeSelected);
   m_actions.push_back(action);
 
   // initialize the calculators
diff --git a/avogadro/qtplugins/forcefield/forcefielddialog.cpp b/avogadro/qtplugins/forcefield/forcefielddialog.cpp
index 6997467780..dde522d41c 100644
--- a/avogadro/qtplugins/forcefield/forcefielddialog.cpp
+++ b/avogadro/qtplugins/forcefield/forcefielddialog.cpp
@@ -24,8 +24,8 @@ ForceFieldDialog::ForceFieldDialog(const QStringList& forceFields,
   ui->forceField->addItems(forceFields);
   updateRecommendedForceField();
 
-  connect(ui->useRecommended, SIGNAL(toggled(bool)),
-          SLOT(useRecommendedForceFieldToggled(bool)));
+  connect(ui->useRecommended, &QAbstractButton::toggled, this,
+          &ForceFieldDialog::useRecommendedForceFieldToggled);
 
   QSettings settings;
   bool autoDetect =
diff --git a/avogadro/qtplugins/forcefield/obmmenergy.cpp b/avogadro/qtplugins/forcefield/obmmenergy.cpp
index 49c67194be..f8f3c22478 100644
--- a/avogadro/qtplugins/forcefield/obmmenergy.cpp
+++ b/avogadro/qtplugins/forcefield/obmmenergy.cpp
@@ -18,12 +18,12 @@
 namespace Avogadro::QtPlugins {
 
 OBMMEnergy::OBMMEnergy(const std::string& method)
-  : m_identifier(method), m_name(method), m_process(nullptr),
-    m_molecule(nullptr),
+  : m_molecule(nullptr), m_process(nullptr), m_executable("obmm"),
+    m_identifier(method),
 #if defined(_WIN32)
     m_executable("obmm.exe")
 #else
-    m_executable("obmm")
+    m_name(method)
 #endif
 {
   // eventually CJSON might be nice
diff --git a/avogadro/qtplugins/forcefield/scriptenergy.cpp b/avogadro/qtplugins/forcefield/scriptenergy.cpp
index 1a117b94a2..d81ea28af8 100644
--- a/avogadro/qtplugins/forcefield/scriptenergy.cpp
+++ b/avogadro/qtplugins/forcefield/scriptenergy.cpp
@@ -30,8 +30,8 @@
 namespace Avogadro::QtPlugins {
 
 ScriptEnergy::ScriptEnergy(const QString& scriptFileName_)
-  : m_interpreter(new QtGui::PythonScript(scriptFileName_)), m_valid(true),
-    m_inputFormat(NotUsed), m_gradients(false), m_ions(false),
+  : m_interpreter(new QtGui::PythonScript(scriptFileName_)),
+    m_inputFormat(NotUsed), m_valid(true), m_gradients(false), m_ions(false),
     m_radicals(false), m_unitCells(false)
 {
   m_elements.reset();
diff --git a/avogadro/qtplugins/gamessinput/gamessinput.cpp b/avogadro/qtplugins/gamessinput/gamessinput.cpp
index 4328bd0188..598ef463f1 100644
--- a/avogadro/qtplugins/gamessinput/gamessinput.cpp
+++ b/avogadro/qtplugins/gamessinput/gamessinput.cpp
@@ -32,7 +32,7 @@ GamessInput::GamessInput(QObject* parent_)
 {
   m_action->setEnabled(true);
   m_action->setText(tr("&GAMESS…"));
-  connect(m_action, SIGNAL(triggered()), SLOT(menuActivated()));
+  connect(m_action, &QAction::triggered, this, &GamessInput::menuActivated);
 }
 
 GamessInput::~GamessInput() {}
@@ -99,8 +99,8 @@ void GamessInput::menuActivated()
 {
   if (!m_dialog) {
     m_dialog = new GamessInputDialog(qobject_cast<QWidget*>(parent()));
-    connect(m_dialog, SIGNAL(openJobOutput(Avogadro::MoleQueue::JobObject)),
-            this, SLOT(openJobOutput(Avogadro::MoleQueue::JobObject)));
+    connect(m_dialog, &GamessInputDialog::openJobOutput, this,
+            &GamessInput::openJobOutput);
   }
   m_dialog->setMolecule(m_molecule);
   m_dialog->show();
diff --git a/avogadro/qtplugins/gamessinput/gamessinputdialog.cpp b/avogadro/qtplugins/gamessinput/gamessinputdialog.cpp
index 2d2297da42..9dbf18f9fa 100644
--- a/avogadro/qtplugins/gamessinput/gamessinputdialog.cpp
+++ b/avogadro/qtplugins/gamessinput/gamessinputdialog.cpp
@@ -129,8 +129,10 @@ void GamessInputDialog::setMolecule(QtGui::Molecule* mol)
 
   m_molecule = mol;
 
-  connect(mol, SIGNAL(changed(unsigned int)), SLOT(updatePreviewText()));
-  connect(mol, SIGNAL(changed(unsigned int)), SLOT(updateTitlePlaceholder()));
+  connect(mol, &QtGui::Molecule::changed, this,
+          &GamessInputDialog::updatePreviewText);
+  connect(mol, &QtGui::Molecule::changed, this,
+          &GamessInputDialog::updateTitlePlaceholder);
 
   updateTitlePlaceholder();
   updatePreviewText();
@@ -143,13 +145,13 @@ void GamessInputDialog::showEvent(QShowEvent* e)
   // Update the preview text if an update was requested while hidden. Use a
   // single shot to allow the dialog to show before popping up any warnings.
   if (m_updatePending)
-    QTimer::singleShot(0, this, SLOT(updatePreviewText()));
+    QTimer::singleShot(0, this, &GamessInputDialog::updatePreviewText);
 }
 
 void GamessInputDialog::connectBasic()
 {
-  connect(ui.titleEdit, SIGNAL(textChanged(QString)), this,
-          SLOT(updatePreviewText()));
+  connect(ui.titleEdit, &QLineEdit::textChanged, this,
+          &GamessInputDialog::updatePreviewText);
   connect(ui.calculateCombo, SIGNAL(currentIndexChanged(int)), this,
           SLOT(updatePreviewText()));
   connect(ui.calculateCombo, SIGNAL(currentIndexChanged(int)), this,
@@ -174,11 +176,15 @@ void GamessInputDialog::connectPreview() {}
 
 void GamessInputDialog::connectButtons()
 {
-  connect(ui.resetAllButton, SIGNAL(clicked()), SLOT(resetClicked()));
-  connect(ui.defaultsButton, SIGNAL(clicked()), SLOT(defaultsClicked()));
-  connect(ui.generateButton, SIGNAL(clicked()), SLOT(generateClicked()));
-  connect(ui.computeButton, SIGNAL(clicked()), SLOT(computeClicked()));
-  connect(ui.closeButton, SIGNAL(clicked()), SLOT(close()));
+  connect(ui.resetAllButton, &QAbstractButton::clicked, this,
+          &GamessInputDialog::resetClicked);
+  connect(ui.defaultsButton, &QAbstractButton::clicked, this,
+          &GamessInputDialog::defaultsClicked);
+  connect(ui.generateButton, &QAbstractButton::clicked, this,
+          &GamessInputDialog::generateClicked);
+  connect(ui.computeButton, &QAbstractButton::clicked, this,
+          &GamessInputDialog::computeClicked);
+  connect(ui.closeButton, &QAbstractButton::clicked, this, &QWidget::close);
 }
 
 void GamessInputDialog::buildOptions()
diff --git a/avogadro/qtplugins/hydrogens/hydrogens.cpp b/avogadro/qtplugins/hydrogens/hydrogens.cpp
index b4cb3a2c7a..11a219dadf 100644
--- a/avogadro/qtplugins/hydrogens/hydrogens.cpp
+++ b/avogadro/qtplugins/hydrogens/hydrogens.cpp
@@ -8,8 +8,8 @@
 #include <avogadro/qtgui/hydrogentools.h>
 #include <avogadro/qtgui/molecule.h>
 
-#include <QtGui/QKeySequence>
 #include <QAction>
+#include <QtGui/QKeySequence>
 
 #include <QtCore/QStringList>
 
@@ -21,28 +21,26 @@ Hydrogens::Hydrogens(QObject* parent_)
   auto* action = new QAction(tr("&Adjust Hydrogens"), this);
   action->setShortcut(QKeySequence("Ctrl+Alt+H"));
   action->setProperty("menu priority", 760);
-  connect(action, SIGNAL(triggered()), SLOT(adjustHydrogens()));
+  connect(action, &QAction::triggered, this, &Hydrogens::adjustHydrogens);
   m_actions.append(action);
 
   action = new QAction(tr("Add Hydrogens"), this);
   action->setProperty("menu priority", 750);
-  connect(action, SIGNAL(triggered()), SLOT(addHydrogens()));
+  connect(action, &QAction::triggered, this, &Hydrogens::addHydrogens);
   m_actions.append(action);
 
   action = new QAction(tr("Remove E&xtra Hydrogens"), this);
   action->setProperty("menu priority", 740);
-  connect(action, SIGNAL(triggered()), SLOT(removeHydrogens()));
+  connect(action, &QAction::triggered, this, &Hydrogens::removeHydrogens);
   m_actions.append(action);
 
   action = new QAction(tr("&Remove All Hydrogens"), this);
   action->setProperty("menu priority", 730);
-  connect(action, SIGNAL(triggered()), SLOT(removeAllHydrogens()));
+  connect(action, &QAction::triggered, this, &Hydrogens::removeAllHydrogens);
   m_actions.append(action);
 }
 
-Hydrogens::~Hydrogens()
-{
-}
+Hydrogens::~Hydrogens() {}
 
 QString Hydrogens::description() const
 {
@@ -107,4 +105,4 @@ void Hydrogens::removeAllHydrogens()
   }
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/importpqr/importpqr.cpp b/avogadro/qtplugins/importpqr/importpqr.cpp
index 8038ca713a..9c8aa62b39 100644
--- a/avogadro/qtplugins/importpqr/importpqr.cpp
+++ b/avogadro/qtplugins/importpqr/importpqr.cpp
@@ -23,11 +23,11 @@ ImportPQR::ImportPQR(QObject* parent_)
 {
   m_action->setEnabled(false);
   m_action->setText(tr("&Search PQR…"));
-  connect(m_action, SIGNAL(triggered()), SLOT(menuActivated()));
+  connect(m_action, &QAction::triggered, this, &ImportPQR::menuActivated);
 
   // check if PQR is up
-  connect(m_manager, SIGNAL(finished(QNetworkReply*)),
-          SLOT(checkAccess(QNetworkReply*)));
+  connect(m_manager, &QNetworkAccessManager::finished, this,
+          &ImportPQR::checkAccess);
   m_manager->get(QNetworkRequest(QUrl("https://pqr.pitt.edu")));
 }
 
diff --git a/avogadro/qtplugins/importpqr/pqrrequest.cpp b/avogadro/qtplugins/importpqr/pqrrequest.cpp
index 76753cb986..fadd3952e8 100644
--- a/avogadro/qtplugins/importpqr/pqrrequest.cpp
+++ b/avogadro/qtplugins/importpqr/pqrrequest.cpp
@@ -9,9 +9,9 @@ using json = nlohmann::json;
 
 namespace Avogadro::QtPlugins {
 /**
-* @brief Constructor to initialize the NetworkAccessManager and set pointers to
-* the widget's ui elements.
-*/
+ * @brief Constructor to initialize the NetworkAccessManager and set pointers to
+ * the widget's ui elements.
+ */
 PQRRequest::PQRRequest(QTableWidget* tw, QLabel* gv, QLineEdit* nd, QLabel* fd,
                        PQRWidget* w)
 {
@@ -27,51 +27,51 @@ PQRRequest::PQRRequest(QTableWidget* tw, QLabel* gv, QLineEdit* nd, QLabel* fd,
 }
 
 /**
-* @brief Free the ui pointers
-*/
+ * @brief Free the ui pointers
+ */
 PQRRequest::~PQRRequest()
 {
   delete oNetworkAccessManager;
 }
 
 /**
-* @brief Sends a network request to search for molecules from PQR;
-* @param url The url to query
-*/
+ * @brief Sends a network request to search for molecules from PQR;
+ * @param url The url to query
+ */
 void PQRRequest::sendRequest(QString url)
 {
   reply = oNetworkAccessManager->get(QNetworkRequest(QUrl(url)));
-  connect(reply, SIGNAL(finished()), this, SLOT(parseJson()));
+  connect(reply, &QNetworkReply::finished, this, &PQRRequest::parseJson);
 }
 
 /**
-* @brief Sends a network request to download a file from PQR
-* @param url The url to send the request to
-* @param mol2 The mol2 representation of the molecule to download
-*/
+ * @brief Sends a network request to download a file from PQR
+ * @param url The url to send the request to
+ * @param mol2 The mol2 representation of the molecule to download
+ */
 void PQRRequest::sendRequest(QString url, QString)
 {
   reply = oNetworkAccessManager->get(QNetworkRequest(QUrl(url)));
   currentMolName = nameDisplay->text(); // needed to load mol into Avogadro
-  connect(reply, SIGNAL(finished()), this, SLOT(getFile()));
+  connect(reply, &QNetworkReply::finished, this, &PQRRequest::getFile);
 }
 
 /**
-* @brief Sends a network request to download a png form PQR
-* @param url The url to send the request to
-*/
+ * @brief Sends a network request to download a png form PQR
+ * @param url The url to send the request to
+ */
 void PQRRequest::sendPNGRequest(QString url)
 {
   reply = oNetworkAccessManager->get(QNetworkRequest(QUrl(url)));
-  connect(reply, SIGNAL(finished()), this, SLOT(SetPNG()));
+  connect(reply, &QNetworkReply::finished, this, &PQRRequest::SetPNG);
 }
 
 /**
-* @brief Called when a molecule is selected to display information about the
-* molecule and start grabbing the SVG preview.
-* @param num The row number of the table result selected
-* @returns The mol2 of the result for the widget to reference
-*/
+ * @brief Called when a molecule is selected to display information about the
+ * molecule and start grabbing the SVG preview.
+ * @param num The row number of the table result selected
+ * @returns The mol2 of the result for the widget to reference
+ */
 QString PQRRequest::molSelected(int num)
 {
   if (results.empty() || num > static_cast<int>(results.size()))
@@ -88,8 +88,8 @@ QString PQRRequest::molSelected(int num)
 }
 
 /**
-* @brief Parses the JSON response from querying PQR
-*/
+ * @brief Parses the JSON response from querying PQR
+ */
 void PQRRequest::parseJson()
 {
   if (reply->error() == QNetworkReply::NoError) {
@@ -152,8 +152,8 @@ void PQRRequest::parseJson()
 }
 
 /**
-* @brief Creates a file after requesting a file from PQR
-*/
+ * @brief Creates a file after requesting a file from PQR
+ */
 void PQRRequest::getFile()
 {
   QByteArray molData = reply->readAll();
@@ -162,8 +162,8 @@ void PQRRequest::getFile()
 }
 
 /**
-* @brief Loads PNG data after sending a request
-*/
+ * @brief Loads PNG data after sending a request
+ */
 void PQRRequest::SetPNG()
 {
   QByteArray pngData = reply->readAll();
@@ -172,9 +172,9 @@ void PQRRequest::SetPNG()
 }
 
 /**
-* @brief Takes a formula string and returns a QString with subscript tags
-* @param formula The formula string
-*/
+ * @brief Takes a formula string and returns a QString with subscript tags
+ * @param formula The formula string
+ */
 QString PQRRequest::parseSubscripts(QString formula)
 {
   std::string str = formula.toStdString();
@@ -192,9 +192,9 @@ QString PQRRequest::parseSubscripts(QString formula)
 }
 
 /**
-* @brief Takes a formula string and returns the molecular mass of the molecule
-* @param formula The formula string
-*/
+ * @brief Takes a formula string and returns the molecular mass of the molecule
+ * @param formula The formula string
+ */
 float PQRRequest::getMolMass(QString formula)
 {
   std::string str = formula.toStdString();
@@ -244,4 +244,4 @@ float PQRRequest::getMolMass(QString formula)
   }
   return totalMass;
 }
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/importpqr/pqrwidget.cpp b/avogadro/qtplugins/importpqr/pqrwidget.cpp
index 2156da1ed5..d643b5cf25 100644
--- a/avogadro/qtplugins/importpqr/pqrwidget.cpp
+++ b/avogadro/qtplugins/importpqr/pqrwidget.cpp
@@ -19,10 +19,12 @@ PQRWidget::PQRWidget(QWidget* parent, ImportPQR* p)
   ui->tableWidget->setEditTriggers(QAbstractItemView::NoEditTriggers);
   ui->tableWidget->setSelectionBehavior(QAbstractItemView::SelectRows);
   ui->tableWidget->setSortingEnabled(true);
-  connect(ui->searchButton, SIGNAL(clicked(bool)), this, SLOT(searchAction()));
-  connect(ui->downloadButton, SIGNAL(clicked(bool)), this, SLOT(downloadMol()));
-  connect(ui->tableWidget, SIGNAL(cellClicked(int, int)), this,
-          SLOT(molSelected(int, int)));
+  connect(ui->searchButton, &QAbstractButton::clicked, this,
+          &PQRWidget::searchAction);
+  connect(ui->downloadButton, &QAbstractButton::clicked, this,
+          &PQRWidget::downloadMol);
+  connect(ui->tableWidget, &QTableWidget::cellClicked, this,
+          &PQRWidget::molSelected);
 
   request = new PQRRequest(ui->tableWidget, ui->pngPreview, ui->nameDisplay,
                            ui->formulaDisplay, this);
@@ -35,8 +37,8 @@ PQRWidget::~PQRWidget()
 }
 
 /**
-* @brief Called when the search button is clicked to send a query to PQR
-*/
+ * @brief Called when the search button is clicked to send a query to PQR
+ */
 void PQRWidget::searchAction()
 {
   ui->downloadButton->setEnabled(false);
@@ -46,12 +48,12 @@ void PQRWidget::searchAction()
 }
 
 /**
-* @brief Called when a table result is double clicked to display preview
-* information
-* about the result before downloading.
-* @param row The row of the result selected.
-* @param col The column of the result selected.
-*/
+ * @brief Called when a table result is double clicked to display preview
+ * information
+ * about the result before downloading.
+ * @param row The row of the result selected.
+ * @param col The column of the result selected.
+ */
 void PQRWidget::molSelected(int row, int)
 {
   currentlySelectedMol = request->molSelected(row);
@@ -62,8 +64,8 @@ void PQRWidget::molSelected(int row, int)
 }
 
 /**
-* @brief Called when PNG data is ready to be loaded
-*/
+ * @brief Called when PNG data is ready to be loaded
+ */
 void PQRWidget::loadPNG(QByteArray& pngData)
 {
   QPixmap pixmap;
@@ -74,10 +76,10 @@ void PQRWidget::loadPNG(QByteArray& pngData)
 }
 
 /**
-* @brief Called when the download button is clicked to send a request to
-* download
-* molecule information from PQR.
-*/
+ * @brief Called when the download button is clicked to send a request to
+ * download
+ * molecule information from PQR.
+ */
 void PQRWidget::downloadMol()
 {
   QString mol2url = currentlySelectedMol;
@@ -93,4 +95,4 @@ void PQRWidget::loadMolecule(QByteArray& molData, QString name)
   plugin->setMoleculeData(molData, name);
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/insertdna/insertdna.cpp b/avogadro/qtplugins/insertdna/insertdna.cpp
index 2e539d5b09..b1ce235488 100644
--- a/avogadro/qtplugins/insertdna/insertdna.cpp
+++ b/avogadro/qtplugins/insertdna/insertdna.cpp
@@ -42,7 +42,7 @@ InsertDna::InsertDna(QObject* p)
 {
   auto* action = new QAction(tr("DNA/RNA…"), this);
   action->setProperty("menu priority", 870);
-  connect(action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(action, &QAction::triggered, this, &InsertDna::showDialog);
 
   m_actions.append(action);
 }
@@ -101,8 +101,8 @@ void InsertDna::constructDialog()
     numStrands->addButton(m_dialog->doubleStrandRadio, 1);
     numStrands->setExclusive(true);
 
-    connect(m_dialog->insertButton, SIGNAL(clicked()), this,
-            SLOT(performInsert()));
+    connect(m_dialog->insertButton, &QAbstractButton::clicked, this,
+            &InsertDna::performInsert);
 
     connect(m_dialog->bpCombo, SIGNAL(currentIndexChanged(int)), this,
             SLOT(updateBPTurns(int)));
@@ -112,9 +112,9 @@ void InsertDna::constructDialog()
 
     // Set the nucleic buttons to update the sequence
     foreach (const QToolButton* child, m_dialog->findChildren<QToolButton*>()) {
-      connect(child, SIGNAL(clicked()), this, SLOT(updateText()));
+      connect(child, &QAbstractButton::clicked, this, &InsertDna::updateText);
     }
-    connect(m_dialog, SIGNAL(destroyed()), this, SLOT(dialogDestroyed()));
+    connect(m_dialog, &QObject::destroyed, this, &InsertDna::dialogDestroyed);
   }
   m_dialog->sequenceText->setPlainText(QString());
 }
diff --git a/avogadro/qtplugins/insertfragment/insertfragment.cpp b/avogadro/qtplugins/insertfragment/insertfragment.cpp
index 7c9a42895f..5af8eacd34 100644
--- a/avogadro/qtplugins/insertfragment/insertfragment.cpp
+++ b/avogadro/qtplugins/insertfragment/insertfragment.cpp
@@ -26,19 +26,19 @@ using Avogadro::QtGui::Molecule;
 namespace Avogadro::QtPlugins {
 
 InsertFragment::InsertFragment(QObject* parent_)
-  : Avogadro::QtGui::ExtensionPlugin(parent_), m_crystalDialog(nullptr),
-    m_moleculeDialog(nullptr), m_reader(nullptr), m_molecule(nullptr)
+  : Avogadro::QtGui::ExtensionPlugin(parent_), m_moleculeDialog(nullptr),
+    m_crystalDialog(nullptr), m_molecule(nullptr), m_reader(nullptr)
 {
   auto* action = new QAction(tr("Molecule…"), this);
   action->setProperty("menu priority", 890);
   action->setData("molecules"); // will also work for crystals
-  connect(action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(action, &QAction::triggered, this, &InsertFragment::showDialog);
   m_actions.append(action);
 
   action = new QAction(tr("Crystal…"), this);
   action->setData("crystals"); // will also work for crystals
   action->setProperty("menu priority", 170);
-  connect(action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(action, &QAction::triggered, this, &InsertFragment::showDialog);
   m_actions.append(action);
 }
 
diff --git a/avogadro/qtplugins/label/label.cpp b/avogadro/qtplugins/label/label.cpp
index 57f59a7341..f59cf42e32 100644
--- a/avogadro/qtplugins/label/label.cpp
+++ b/avogadro/qtplugins/label/label.cpp
@@ -155,8 +155,8 @@ struct LayerLabel : Core::LayerData
       auto* form = new QFormLayout;
       // color button
       auto* colorButton = new QtGui::ColorButton;
-      QObject::connect(colorButton, SIGNAL(colorChanged(const QColor&)), slot,
-                       SLOT(setColor(const QColor&)));
+      QObject::connect(colorButton, &QtGui::ColorButton::colorChanged, slot,
+                       &Label::setColor);
       form->addRow(QObject::tr("Color:"), colorButton);
 
       // radius scalar
diff --git a/avogadro/qtplugins/lammpsinput/lammpsinput.cpp b/avogadro/qtplugins/lammpsinput/lammpsinput.cpp
index 40e14057d6..d7cd5fba91 100644
--- a/avogadro/qtplugins/lammpsinput/lammpsinput.cpp
+++ b/avogadro/qtplugins/lammpsinput/lammpsinput.cpp
@@ -28,12 +28,10 @@ LammpsInput::LammpsInput(QObject* parent_)
 {
   m_action->setEnabled(true);
   m_action->setText(tr("&LAMMPS…"));
-  connect(m_action, SIGNAL(triggered()), SLOT(menuActivated()));
+  connect(m_action, &QAction::triggered, this, &LammpsInput::menuActivated);
 }
 
-LammpsInput::~LammpsInput()
-{
-}
+LammpsInput::~LammpsInput() {}
 
 QList<QAction*> LammpsInput::actions() const
 {
@@ -81,5 +79,5 @@ void LammpsInput::menuActivated()
   m_dialog->setMolecule(m_molecule);
   m_dialog->show();
 }
-}
-}
+} // namespace QtPlugins
+} // namespace Avogadro
diff --git a/avogadro/qtplugins/lammpsinput/lammpsinputdialog.cpp b/avogadro/qtplugins/lammpsinput/lammpsinputdialog.cpp
index 95da2615e0..495d09241a 100644
--- a/avogadro/qtplugins/lammpsinput/lammpsinputdialog.cpp
+++ b/avogadro/qtplugins/lammpsinput/lammpsinputdialog.cpp
@@ -54,7 +54,8 @@ LammpsInputDialog::LammpsInputDialog(QWidget* parent, Qt::WindowFlags flag)
 {
   ui.setupUi(this);
   // Connect the GUI elements to the correct slots
-  connect(ui.titleLine, SIGNAL(editingFinished()), this, SLOT(setTitle()));
+  connect(ui.titleLine, &QLineEdit::editingFinished, this,
+          &LammpsInputDialog::setTitle);
 
   // now for something useful
   connect(ui.unitsCombo, SIGNAL(currentIndexChanged(int)), this,
@@ -71,8 +72,8 @@ LammpsInputDialog::LammpsInputDialog(QWidget* parent, Qt::WindowFlags flag)
           SLOT(setZBoundaryType(int)));
   connect(ui.waterPotentialCombo, SIGNAL(currentIndexChanged(int)), this,
           SLOT(setWaterPotential(int)));
-  connect(ui.readDataLine, SIGNAL(editingFinished()), this,
-          SLOT(setReadData()));
+  connect(ui.readDataLine, &QLineEdit::editingFinished, this,
+          &LammpsInputDialog::setReadData);
   connect(ui.ensembleCombo, SIGNAL(currentIndexChanged(int)), this,
           SLOT(setEnsemble(int)));
   connect(ui.tempSpin, SIGNAL(valueChanged(double)), this,
@@ -88,25 +89,30 @@ LammpsInputDialog::LammpsInputDialog(QWidget* parent, Qt::WindowFlags flag)
           SLOT(setYReplicate(int)));
   connect(ui.zReplicateSpin, SIGNAL(valueChanged(int)), this,
           SLOT(setZReplicate(int)));
-  connect(ui.dumpXYZEdit, SIGNAL(editingFinished()), this, SLOT(setDumpXYZ()));
+  connect(ui.dumpXYZEdit, &QLineEdit::editingFinished, this,
+          &LammpsInputDialog::setDumpXYZ);
   connect(ui.dumpStepSpin, SIGNAL(valueChanged(int)), this,
           SLOT(setDumpStep(int)));
   connect(ui.velocityDistCombo, SIGNAL(currentIndexChanged(int)), this,
           SLOT(setVelocityDist(int)));
   connect(ui.velocityTempSpin, SIGNAL(valueChanged(double)), this,
           SLOT(setVelocityTemp(double)));
-  connect(ui.zeroMOMCheck, SIGNAL(toggled(bool)), this, SLOT(setZeroMOM(bool)));
-  connect(ui.zeroLCheck, SIGNAL(toggled(bool)), this, SLOT(setZeroL(bool)));
+  connect(ui.zeroMOMCheck, &QAbstractButton::toggled, this,
+          &LammpsInputDialog::setZeroMOM);
+  connect(ui.zeroLCheck, &QAbstractButton::toggled, this,
+          &LammpsInputDialog::setZeroL);
   connect(ui.thermoStyleCombo, SIGNAL(currentIndexChanged(int)), this,
           SLOT(setThermoStyle(int)));
   connect(ui.thermoSpin, SIGNAL(valueChanged(int)), this,
           SLOT(setThermoInterval(int)));
 
-  connect(ui.generateButton, SIGNAL(clicked()), this, SLOT(generateClicked()));
-  connect(ui.resetButton, SIGNAL(clicked()), this, SLOT(resetClicked()));
+  connect(ui.generateButton, &QAbstractButton::clicked, this,
+          &LammpsInputDialog::generateClicked);
+  connect(ui.resetButton, &QAbstractButton::clicked, this,
+          &LammpsInputDialog::resetClicked);
 
-  connect(ui.enableFormButton, SIGNAL(clicked()), this,
-          SLOT(enableFormClicked()));
+  connect(ui.enableFormButton, &QAbstractButton::clicked, this,
+          &LammpsInputDialog::enableFormClicked);
 
   QSettings settings;
   readSettings(settings);
@@ -161,7 +167,8 @@ void LammpsInputDialog::updatePreviewText()
   m_jobEdit = new QTextEdit(this);
   m_jobEdit->setObjectName(m_jobFileName);
   m_jobEdit->setFontFamily("monospace");
-  connect(m_jobEdit, SIGNAL(textChanged()), this, SLOT(textEditModified()));
+  connect(m_jobEdit, &QTextEdit::textChanged, this,
+          &LammpsInputDialog::textEditModified);
   m_jobEdit->setText(generateInputDeck());
   ui.tabWidget->insertTab(jobTabPosition, m_jobEdit, m_jobFileName);
   deckDirty(false);
@@ -310,8 +317,8 @@ void LammpsInputDialog::generateClicked()
           tr("The input files cannot be written:\n\n%1").arg(errors.first());
         break;
       default: {
-        // If a fatal error occurred, it will be last one in the list. Pop it off
-        // and tell the user that it was the reason we had to stop.
+        // If a fatal error occurred, it will be last one in the list. Pop it
+        // off and tell the user that it was the reason we had to stop.
         QString fatal = errors.last();
         QStringList tmp(errors);
         tmp.pop_back();
@@ -473,7 +480,8 @@ void LammpsInputDialog::setMolecule(QtGui::Molecule* molecule)
 
   m_molecule = molecule;
   // Update the preview text whenever primitives are changed
-  connect(molecule, SIGNAL(changed(unsigned int)), SLOT(updatePreviewText()));
+  connect(molecule, &QtGui::Molecule::changed, this,
+          &LammpsInputDialog::updatePreviewText);
   updatePreviewText();
 }
 
@@ -632,8 +640,8 @@ QString LammpsInputDialog::generateInputDeck()
       << "mom " << getZeroMOM() << " "
       << "dist " << getVelocityDist(m_velocityDist) << "\n";
   mol << getEnsemble(m_ensemble) << "\n";
-  mol << "timestep       " << Qt::fixed << qSetRealNumberPrecision(1) << m_timeStep
-      << "\n";
+  mol << "timestep       " << Qt::fixed << qSetRealNumberPrecision(1)
+      << m_timeStep << "\n";
   mol << "\n";
 
   mol << "# Output\n";
@@ -853,9 +861,9 @@ QString LammpsInputDialog::getEnsemble(ensemble t)
       QString ensembleInput;
       QTextStream fix(&ensembleInput);
       fix << "fix            ensemble all nvt"
-          << " temp " << Qt::fixed << qSetRealNumberPrecision(2) << m_temperature
-          << " " << Qt::fixed << qSetRealNumberPrecision(2) << m_temperature
-          << " 100 "
+          << " temp " << Qt::fixed << qSetRealNumberPrecision(2)
+          << m_temperature << " " << Qt::fixed << qSetRealNumberPrecision(2)
+          << m_temperature << " 100 "
           << "tchain " << m_nhChain << "\n";
       return ensembleInput;
     }
@@ -869,9 +877,9 @@ QString LammpsInputDialog::getEnsemble(ensemble t)
       QString ensembleInput;
       QTextStream fix(&ensembleInput);
       fix << "fix            ensemble all nvt"
-          << " temp " << Qt::fixed << qSetRealNumberPrecision(2) << m_temperature
-          << " " << Qt::fixed << qSetRealNumberPrecision(2) << m_temperature
-          << " 100 "
+          << " temp " << Qt::fixed << qSetRealNumberPrecision(2)
+          << m_temperature << " " << Qt::fixed << qSetRealNumberPrecision(2)
+          << m_temperature << " 100 "
           << "tchain " << m_nhChain << "\n";
       return ensembleInput;
     }
@@ -964,4 +972,4 @@ void LammpsInputDialog::determineAtomTypesSPC(int& hyd, int& oxy)
   hyd = AtomType.value("O");
   oxy = AtomType.value("H");
 }
-}
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/lineformatinput/lineformatinput.cpp b/avogadro/qtplugins/lineformatinput/lineformatinput.cpp
index ca5837e798..1583b632ac 100644
--- a/avogadro/qtplugins/lineformatinput/lineformatinput.cpp
+++ b/avogadro/qtplugins/lineformatinput/lineformatinput.cpp
@@ -25,19 +25,19 @@ using Avogadro::QtGui::FileFormatDialog;
 namespace Avogadro::QtPlugins {
 
 LineFormatInput::LineFormatInput(QObject* parent_)
-  : Avogadro::QtGui::ExtensionPlugin(parent_),
-    m_molecule(nullptr), m_reader(nullptr)
+  : Avogadro::QtGui::ExtensionPlugin(parent_), m_molecule(nullptr),
+    m_reader(nullptr)
 {
   auto* action = new QAction(tr("SMILES…"), this);
   action->setProperty("menu priority", 800);
   action->setData("SMILES");
-  connect(action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(action, &QAction::triggered, this, &LineFormatInput::showDialog);
   m_actions.append(action);
 
   action = new QAction(tr("InChI…"), this);
   action->setProperty("menu priority", 810);
   action->setData("InChI");
-  connect(action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(action, &QAction::triggered, this, &LineFormatInput::showDialog);
   m_actions.append(action);
 
   // These are the line formats that we can load -- key is a user-friendly name,
@@ -137,4 +137,4 @@ void LineFormatInput::showDialog()
   m_reader = nullptr;
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/manipulator/manipulator.cpp b/avogadro/qtplugins/manipulator/manipulator.cpp
index 5eeeb9b761..49ba1ba6ff 100644
--- a/avogadro/qtplugins/manipulator/manipulator.cpp
+++ b/avogadro/qtplugins/manipulator/manipulator.cpp
@@ -54,8 +54,8 @@ Manipulator::Manipulator(QObject* parent_)
        "Right Mouse: \tClick and drag to rotate atoms.\n")
       .arg(shortcut));
   setIcon();
-  connect(m_toolWidget->buttonBox, SIGNAL(clicked(QAbstractButton*)), this,
-          SLOT(buttonClicked(QAbstractButton*)));
+  connect(m_toolWidget->buttonBox, &QDialogButtonBox::clicked, this,
+          &Manipulator::buttonClicked);
 }
 
 Manipulator::~Manipulator() {}
diff --git a/avogadro/qtplugins/meshes/meshes.cpp b/avogadro/qtplugins/meshes/meshes.cpp
index a99587fc5a..28bfea5091 100644
--- a/avogadro/qtplugins/meshes/meshes.cpp
+++ b/avogadro/qtplugins/meshes/meshes.cpp
@@ -80,24 +80,26 @@ void Meshes::process(const QtGui::Molecule& mol, GroupNode& node)
       auto colors = mesh->colors();
       Core::Array<Vector3ub> colorsRGB(colors.size());
       for (size_t i = 0; i < colors.size(); i++)
-        colorsRGB[i] = Vector3ub(static_cast<unsigned char>(colors[i].red() * 255),
-                                 static_cast<unsigned char>(colors[i].green() * 255),
-                                 static_cast<unsigned char>(colors[i].blue() * 255));
+        colorsRGB[i] =
+          Vector3ub(static_cast<unsigned char>(colors[i].red() * 255),
+                    static_cast<unsigned char>(colors[i].green() * 255),
+                    static_cast<unsigned char>(colors[i].blue() * 255));
       mesh1->addVertices(mesh->vertices(), mesh->normals(), colorsRGB);
     } else {
       mesh1->setColor(m_color1);
       mesh1->addVertices(mesh->vertices(), mesh->normals());
-    }   
+    }
 
     // Add the triangles for the first mesh
     for (size_t i = 0; i < triangles.size(); ++i) {
       mesh1->addTriangle(triangles[i][0], triangles[i][1], triangles[i][2]);
     }
 
-    mesh1->setRenderPass(m_opacity == 255 ? Rendering::SolidPass : Rendering::TranslucentPass);
+    mesh1->setRenderPass(m_opacity == 255 ? Rendering::SolidPass
+                                          : Rendering::TranslucentPass);
 
     // Handle the second mesh if present
-    if (mol.meshCount() >= 2) { 
+    if (mol.meshCount() >= 2) {
       auto* mesh2 = new MeshGeometry;
       geometry->addDrawable(mesh2);
 
@@ -112,7 +114,8 @@ void Meshes::process(const QtGui::Molecule& mol, GroupNode& node)
 
       // Add the correct triangles for the second mesh
       for (size_t i = 0; i < triangles2.size(); ++i) {
-        mesh2->addTriangle(triangles2[i][0], triangles2[i][1], triangles2[i][2]);
+        mesh2->addTriangle(triangles2[i][0], triangles2[i][1],
+                           triangles2[i][2]);
       }
 
       mesh2->setRenderPass(m_opacity == 255 ? Rendering::SolidPass
@@ -165,21 +168,21 @@ QWidget* Meshes::setupWidget()
     slide->setRange(0, 255);
     slide->setTickInterval(5);
     slide->setValue(m_opacity);
-    connect(slide, SIGNAL(valueChanged(int)), SLOT(setOpacity(int)));
+    connect(slide, &QAbstractSlider::valueChanged, this, &Meshes::setOpacity);
 
     auto* form = new QFormLayout;
     form->addRow(tr("Opacity:"), slide);
 
     auto* color1 = new QtGui::ColorButton;
     color1->setColor(QColor(m_color1[0], m_color1[1], m_color1[2]));
-    connect(color1, SIGNAL(colorChanged(const QColor&)),
-            SLOT(setColor1(const QColor&)));
+    connect(color1, &QtGui::ColorButton::colorChanged, this,
+            &Meshes::setColor1);
     form->addRow(tr("Color:"), color1);
 
     auto* color2 = new QtGui::ColorButton;
     color2->setColor(QColor(m_color2[0], m_color2[1], m_color2[2]));
-    connect(color2, SIGNAL(colorChanged(const QColor&)),
-            SLOT(setColor2(const QColor&)));
+    connect(color2, &QtGui::ColorButton::colorChanged, this,
+            &Meshes::setColor2);
     form->addRow(tr("Color:"), color2);
 
     v->addLayout(form);
diff --git a/avogadro/qtplugins/molecularproperties/molecularmodel.cpp b/avogadro/qtplugins/molecularproperties/molecularmodel.cpp
index 2df78ec083..b7a51d9ac0 100644
--- a/avogadro/qtplugins/molecularproperties/molecularmodel.cpp
+++ b/avogadro/qtplugins/molecularproperties/molecularmodel.cpp
@@ -40,8 +40,8 @@ MolecularModel::MolecularModel(QObject* parent)
   : QAbstractTableModel(parent), m_molecule(nullptr)
 {
   m_network = new QNetworkAccessManager(this);
-  connect(m_network, SIGNAL(finished(QNetworkReply*)), this,
-          SLOT(updateNameReady(QNetworkReply*)));
+  connect(m_network, &QNetworkAccessManager::finished, this,
+          &MolecularModel::updateNameReady);
 }
 
 void MolecularModel::setMolecule(QtGui::Molecule* molecule)
@@ -87,7 +87,7 @@ QString MolecularModel::name() const
   m_network->get(QNetworkRequest(QUrl(requestURL)));
 
   // don't update again until we're ready - 5 seconds
-  QTimer::singleShot(5000, this, SLOT(canUpdateName()));
+  QTimer::singleShot(5000, this, &MolecularModel::canUpdateName);
 
   return m_name;
 }
diff --git a/avogadro/qtplugins/molecularproperties/molecularproperties.cpp b/avogadro/qtplugins/molecularproperties/molecularproperties.cpp
index 955ac66b28..124e5ea010 100644
--- a/avogadro/qtplugins/molecularproperties/molecularproperties.cpp
+++ b/avogadro/qtplugins/molecularproperties/molecularproperties.cpp
@@ -27,7 +27,8 @@ MolecularProperties::MolecularProperties(QObject* parent_)
   m_action->setText(tr("&Molecular…"));
   m_action->setProperty("menu priority", 990);
 
-  connect(m_action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(m_action, &QAction::triggered, this,
+          &MolecularProperties::showDialog);
 }
 
 MolecularProperties::~MolecularProperties() {}
diff --git a/avogadro/qtplugins/navigator/navigator.cpp b/avogadro/qtplugins/navigator/navigator.cpp
index 4672081f7a..a546f3e143 100644
--- a/avogadro/qtplugins/navigator/navigator.cpp
+++ b/avogadro/qtplugins/navigator/navigator.cpp
@@ -42,7 +42,8 @@ Navigator::Navigator(QObject* parent_)
     tr("Navigation Tool \t(%1)\n\n"
        "Left Mouse: \tClick and drag to rotate the view.\n"
        "Middle Mouse: \tClick and drag to zoom in or out.\n"
-       "Right Mouse: \tClick and drag to move the view.\n").arg(shortcut));
+       "Right Mouse: \tClick and drag to move the view.\n")
+      .arg(shortcut));
   setIcon();
   QSettings settings;
   m_zoomDirection = settings.value("navigator/zoom", 1).toInt();
@@ -106,8 +107,8 @@ QWidget* Navigator::toolWidget() const
     swapZoom->setToolTip(
       tr("Default:\t Scroll down to shrink, scroll up to zoom\n"
          "Reversed:\t Scroll up to shrink, scroll down to zoom"));
-    connect(swapZoom, SIGNAL(toggled(bool)), this,
-            SLOT(swapZoomDirection(bool)));
+    connect(swapZoom, &QAbstractButton::toggled, this,
+            &Navigator::swapZoomDirection);
     layout->addWidget(swapZoom);
 
     layout->addStretch(1);
diff --git a/avogadro/qtplugins/networkdatabases/networkdatabases.cpp b/avogadro/qtplugins/networkdatabases/networkdatabases.cpp
index 2c7b754135..21e1fa5b71 100644
--- a/avogadro/qtplugins/networkdatabases/networkdatabases.cpp
+++ b/avogadro/qtplugins/networkdatabases/networkdatabases.cpp
@@ -8,9 +8,9 @@
 #include <avogadro/io/fileformatmanager.h>
 #include <avogadro/qtgui/molecule.h>
 
+#include <QAction>
 #include <QtNetwork/QNetworkAccessManager>
 #include <QtNetwork/QNetworkReply>
-#include <QAction>
 #include <QtWidgets/QInputDialog>
 #include <QtWidgets/QMessageBox>
 #include <QtWidgets/QProgressDialog>
@@ -24,12 +24,10 @@ NetworkDatabases::NetworkDatabases(QObject* parent_)
   m_action->setEnabled(true);
   m_action->setText("Download by &Name…");
   m_action->setProperty("menu priority", 190);
-  connect(m_action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(m_action, &QAction::triggered, this, &NetworkDatabases::showDialog);
 }
 
-NetworkDatabases::~NetworkDatabases()
-{
-}
+NetworkDatabases::~NetworkDatabases() {}
 
 QList<QAction*> NetworkDatabases::actions() const
 {
@@ -63,8 +61,8 @@ void NetworkDatabases::showDialog()
 {
   if (!m_network) {
     m_network = new QNetworkAccessManager(this);
-    connect(m_network, SIGNAL(finished(QNetworkReply*)), this,
-            SLOT(replyFinished(QNetworkReply*)));
+    connect(m_network, &QNetworkAccessManager::finished, this,
+            &NetworkDatabases::replyFinished);
   }
   if (!m_progressDialog) {
     m_progressDialog = new QProgressDialog(qobject_cast<QWidget*>(parent()));
@@ -80,9 +78,9 @@ void NetworkDatabases::showDialog()
 
   // Hard coding the NIH resolver download URL - this could be used for other
   // services
-  m_network->get(QNetworkRequest(
-    QUrl("https://cactus.nci.nih.gov/chemical/structure/" + structureName +
-         "/file?format=sdf&get3d=true")));
+  m_network->get(
+    QNetworkRequest(QUrl("https://cactus.nci.nih.gov/chemical/structure/" +
+                         structureName + "/file?format=sdf&get3d=true")));
 
   m_moleculeName = structureName;
   m_progressDialog->setLabelText(tr("Querying for %1").arg(structureName));
@@ -115,4 +113,4 @@ void NetworkDatabases::replyFinished(QNetworkReply* reply)
   emit moleculeReady(1);
   reply->deleteLater();
 }
-}
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/openbabel/conformersearchdialog.cpp b/avogadro/qtplugins/openbabel/conformersearchdialog.cpp
index 23b7c13060..438a2226cc 100644
--- a/avogadro/qtplugins/openbabel/conformersearchdialog.cpp
+++ b/avogadro/qtplugins/openbabel/conformersearchdialog.cpp
@@ -15,17 +15,17 @@ ConformerSearchDialog::ConformerSearchDialog(QWidget* parent) : QDialog(parent)
 {
   ui.setupUi(this);
 
-  connect(ui.systematicRadio, SIGNAL(toggled(bool)), this,
-          SLOT(systematicToggled(bool)));
-  connect(ui.randomRadio, SIGNAL(toggled(bool)), this,
-          SLOT(randomToggled(bool)));
-  connect(ui.weightedRadio, SIGNAL(toggled(bool)), this,
-          SLOT(weightedToggled(bool)));
-  connect(ui.geneticRadio, SIGNAL(toggled(bool)), this,
-          SLOT(geneticToggled(bool)));
-
-  connect(ui.buttonBox, SIGNAL(clicked(QAbstractButton*)), this,
-          SLOT(buttonClicked(QAbstractButton*)));
+  connect(ui.systematicRadio, &QAbstractButton::toggled, this,
+          &ConformerSearchDialog::systematicToggled);
+  connect(ui.randomRadio, &QAbstractButton::toggled, this,
+          &ConformerSearchDialog::randomToggled);
+  connect(ui.weightedRadio, &QAbstractButton::toggled, this,
+          &ConformerSearchDialog::weightedToggled);
+  connect(ui.geneticRadio, &QAbstractButton::toggled, this,
+          &ConformerSearchDialog::geneticToggled);
+
+  connect(ui.buttonBox, &QDialogButtonBox::clicked, this,
+          &ConformerSearchDialog::buttonClicked);
 
   m_method = 1; // systematic
   m_numConformers = 100;
diff --git a/avogadro/qtplugins/openbabel/obcharges.cpp b/avogadro/qtplugins/openbabel/obcharges.cpp
index 166310586e..cec94f7701 100644
--- a/avogadro/qtplugins/openbabel/obcharges.cpp
+++ b/avogadro/qtplugins/openbabel/obcharges.cpp
@@ -62,7 +62,7 @@ public slots:
   Array<double> m_output;
 };
 
-OBCharges::OBCharges(const std::string& id) : m_identifier(id), ChargeModel()
+OBCharges::OBCharges(const std::string& id) : ChargeModel(), m_identifier(id)
 {
   // set the element mask based on our type / identifier
   m_elements.reset();
diff --git a/avogadro/qtplugins/openbabel/obfileformat.cpp b/avogadro/qtplugins/openbabel/obfileformat.cpp
index b0184aeca2..ffaafe15a6 100644
--- a/avogadro/qtplugins/openbabel/obfileformat.cpp
+++ b/avogadro/qtplugins/openbabel/obfileformat.cpp
@@ -90,8 +90,8 @@ bool OBFileFormat::read(std::istream& in, Core::Molecule& molecule)
   // Allow blocking until the read is completed.
   OBProcess proc;
   ProcessListener listener;
-  QObject::connect(&proc, SIGNAL(convertFinished(QByteArray)), &listener,
-                   SLOT(responseReceived(QByteArray)));
+  QObject::connect(&proc, &OBProcess::convertFinished, &listener,
+                   &ProcessListener::responseReceived);
 
   // Just grab the first file extension from the list -- all extensions for a
   // given format map to the same parsers in OB.
@@ -263,8 +263,8 @@ bool OBFileFormat::write(std::ostream& out, const Core::Molecule& molecule)
   // Block until the OpenBabel conversion finishes:
   OBProcess proc;
   ProcessListener listener;
-  QObject::connect(&proc, SIGNAL(convertFinished(QByteArray)), &listener,
-                   SLOT(responseReceived(QByteArray)));
+  QObject::connect(&proc, &OBProcess::convertFinished, &listener,
+                   &ProcessListener::responseReceived);
 
   // Just grab the first file extension from the list -- all extensions for a
   // given format map to the same parsers in OB.
diff --git a/avogadro/qtplugins/openbabel/obforcefielddialog.cpp b/avogadro/qtplugins/openbabel/obforcefielddialog.cpp
index fb122b8780..b44dd52312 100644
--- a/avogadro/qtplugins/openbabel/obforcefielddialog.cpp
+++ b/avogadro/qtplugins/openbabel/obforcefielddialog.cpp
@@ -35,8 +35,8 @@ OBForceFieldDialog::OBForceFieldDialog(const QStringList& forceFields,
   ui->forceField->addItems(forceFields);
   updateRecommendedForceField();
 
-  connect(ui->useRecommended, SIGNAL(toggled(bool)),
-          SLOT(useRecommendedForceFieldToggled(bool)));
+  connect(ui->useRecommended, &QAbstractButton::toggled, this,
+          &OBForceFieldDialog::useRecommendedForceFieldToggled);
 
   QSettings settings;
   bool autoDetect =
@@ -323,4 +323,4 @@ void OBForceFieldDialog::updateRecommendedForceField()
   }
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/openbabel/obprocess.cpp b/avogadro/qtplugins/openbabel/obprocess.cpp
index d2d924fc78..b117537c0d 100644
--- a/avogadro/qtplugins/openbabel/obprocess.cpp
+++ b/avogadro/qtplugins/openbabel/obprocess.cpp
@@ -415,8 +415,8 @@ bool OBProcess::optimizeGeometry(const QByteArray& mol,
               << "--log" << options;
 
   // We'll need to read the log (printed to stderr) to update progress
-  connect(m_process, SIGNAL(readyReadStandardError()),
-          SLOT(optimizeGeometryReadLog()));
+  connect(m_process, &QProcess::readyReadStandardError, this,
+          &OBProcess::optimizeGeometryReadLog);
 
   // Initialize the log reader ivars
   m_optimizeGeometryLog.clear();
@@ -449,8 +449,8 @@ bool OBProcess::generateConformers(const QByteArray& mol,
               << "--log" << options;
 
   // We'll need to read the log (printed to stderr) to update progress
-  connect(m_process, SIGNAL(readyReadStandardError()),
-          SLOT(conformerReadLog()));
+  connect(m_process, &QProcess::readyReadStandardError, this,
+          &OBProcess::conformerReadLog);
 
   // Initialize the log reader ivars
   m_optimizeGeometryLog.clear();
@@ -565,8 +565,7 @@ void OBProcess::executeObabel(const QStringList& options, QObject* receiver,
     connect(m_process, SIGNAL(finished(int)), receiver, slot);
     connect(m_process, SIGNAL(errorOccurred(QProcess::ProcessError)), receiver,
             slot);
-    connect(m_process, SIGNAL(errorOccurred(QProcess::ProcessError)), this,
-            SLOT(obError()));
+    connect(m_process, &QProcess::errorOccurred, this, &OBProcess::obError);
   }
 
   // Start process
@@ -587,7 +586,7 @@ void OBProcess::resetState()
   m_aborted = false;
   m_process->disconnect(this);
   disconnect(m_process);
-  connect(this, SIGNAL(aborted()), m_process, SLOT(kill()));
+  connect(this, &OBProcess::aborted, m_process, &QProcess::kill);
 }
 
 } // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/openbabel/openbabel.cpp b/avogadro/qtplugins/openbabel/openbabel.cpp
index c2e0f3f811..4410e5c4eb 100644
--- a/avogadro/qtplugins/openbabel/openbabel.cpp
+++ b/avogadro/qtplugins/openbabel/openbabel.cpp
@@ -45,43 +45,45 @@ OpenBabel::OpenBabel(QObject* p)
   auto* action = new QAction(this);
   action->setEnabled(true);
   action->setText(tr("Optimize Geometry"));
-  connect(action, SIGNAL(triggered()), SLOT(onOptimizeGeometry()));
+  connect(action, &QAction::triggered, this, &OpenBabel::onOptimizeGeometry);
   m_actions.push_back(action);
 
   action = new QAction(this);
   action->setEnabled(true);
   action->setText(tr("Configure Force Field…"));
-  connect(action, SIGNAL(triggered()), SLOT(onConfigureGeometryOptimization()));
+  connect(action, &QAction::triggered, this,
+          &OpenBabel::onConfigureGeometryOptimization);
   m_actions.push_back(action);
 
   action = new QAction(this);
   action->setEnabled(true);
   action->setText(tr("Conformer Search…"));
-  connect(action, SIGNAL(triggered()), SLOT(onConfigureConformerSearch()));
+  connect(action, &QAction::triggered, this,
+          &OpenBabel::onConfigureConformerSearch);
   m_actions.push_back(action);
 
   action = new QAction(this);
   action->setEnabled(true);
   action->setText(tr("Perceive Bonds"));
-  connect(action, SIGNAL(triggered()), SLOT(onPerceiveBonds()));
+  connect(action, &QAction::triggered, this, &OpenBabel::onPerceiveBonds);
   m_actions.push_back(action);
 
   action = new QAction(this);
   action->setEnabled(true);
   action->setText(tr("Add Hydrogens"));
-  connect(action, SIGNAL(triggered()), SLOT(onAddHydrogens()));
+  connect(action, &QAction::triggered, this, &OpenBabel::onAddHydrogens);
   m_actions.push_back(action);
 
   action = new QAction(this);
   action->setEnabled(true);
   action->setText(tr("Add Hydrogens for pH…"));
-  connect(action, SIGNAL(triggered()), SLOT(onAddHydrogensPh()));
+  connect(action, &QAction::triggered, this, &OpenBabel::onAddHydrogensPh);
   m_actions.push_back(action);
 
   action = new QAction(this);
   action->setEnabled(true);
   action->setText(tr("Remove Hydrogens"));
-  connect(action, SIGNAL(triggered()), SLOT(onRemoveHydrogens()));
+  connect(action, &QAction::triggered, this, &OpenBabel::onRemoveHydrogens);
   m_actions.push_back(action);
 
   refreshReadFormats();
@@ -314,8 +316,8 @@ void OpenBabel::refreshForceFields()
   // process for the refresh methods.
   auto* proc = new OBProcess(this);
 
-  connect(proc, SIGNAL(queryForceFieldsFinished(QMultiMap<QString, QString>)),
-          SLOT(handleForceFieldsUpdate(QMultiMap<QString, QString>)));
+  connect(proc, &OBProcess::queryForceFieldsFinished, this,
+          &OpenBabel::handleForceFieldsUpdate);
 
   proc->queryForceFields();
 }
@@ -336,8 +338,8 @@ void OpenBabel::refreshCharges()
   // process for the refresh methods.
   auto* proc = new OBProcess(this);
 
-  connect(proc, SIGNAL(queryChargesFinished(QMultiMap<QString, QString>)),
-          SLOT(handleChargesUpdate(QMultiMap<QString, QString>)));
+  connect(proc, &OBProcess::queryChargesFinished, this,
+          &OpenBabel::handleChargesUpdate);
 
   proc->queryCharges();
 }
@@ -469,12 +471,11 @@ void OpenBabel::onOptimizeGeometry()
   // Connect process
   disconnect(m_process);
   m_process->disconnect(this);
-  connect(m_progress, SIGNAL(canceled()), m_process, SLOT(abort()));
-  connect(m_process,
-          SIGNAL(optimizeGeometryStatusUpdate(int, int, double, double)),
-          SLOT(onOptimizeGeometryStatusUpdate(int, int, double, double)));
-  connect(m_process, SIGNAL(optimizeGeometryFinished(QByteArray)),
-          SLOT(onOptimizeGeometryFinished(QByteArray)));
+  connect(m_progress, &QProgressDialog::canceled, m_process, &OBProcess::abort);
+  connect(m_process, &OBProcess::optimizeGeometryStatusUpdate, this,
+          &OpenBabel::onOptimizeGeometryStatusUpdate);
+  connect(m_process, &OBProcess::optimizeGeometryFinished, this,
+          &OpenBabel::onOptimizeGeometryFinished);
 
   // Generate CML
   std::string mol;
@@ -622,11 +623,11 @@ void OpenBabel::onGenerateConformers()
   // Connect process
   disconnect(m_process);
   m_process->disconnect(this);
-  connect(m_progress, SIGNAL(canceled()), m_process, SLOT(abort()));
-  connect(m_process, SIGNAL(conformerStatusUpdate(int, int, double, double)),
-          SLOT(onConformerStatusUpdate(int, int, double, double)));
-  connect(m_process, SIGNAL(generateConformersFinished(QByteArray)),
-          SLOT(onGenerateConformersFinished(QByteArray)));
+  connect(m_progress, &QProgressDialog::canceled, m_process, &OBProcess::abort);
+  connect(m_process, &OBProcess::conformerStatusUpdate, this,
+          &OpenBabel::onConformerStatusUpdate);
+  connect(m_process, &OBProcess::generateConformersFinished, this,
+          &OpenBabel::onGenerateConformersFinished);
 
   std::string mol;
   if (!Io::FileFormatManager::instance().writeString(*m_molecule, mol,
@@ -753,9 +754,9 @@ void OpenBabel::onPerceiveBonds()
   // Connect process
   disconnect(m_process);
   m_process->disconnect(this);
-  connect(m_progress, SIGNAL(canceled()), m_process, SLOT(abort()));
-  connect(m_process, SIGNAL(convertFinished(QByteArray)),
-          SLOT(onPerceiveBondsFinished(QByteArray)));
+  connect(m_progress, &QProgressDialog::canceled, m_process, &OBProcess::abort);
+  connect(m_process, &OBProcess::convertFinished, this,
+          &OpenBabel::onPerceiveBondsFinished);
 
   m_progress->setLabelText(tr("Converting XYZ to Open Babel with %1…")
                              .arg(m_process->obabelExecutable()));
@@ -841,9 +842,9 @@ void OpenBabel::onAddHydrogens()
   // Connect process
   disconnect(m_process);
   m_process->disconnect(this);
-  connect(m_progress, SIGNAL(canceled()), m_process, SLOT(abort()));
-  connect(m_process, SIGNAL(convertFinished(QByteArray)),
-          SLOT(onHydrogenOperationFinished(QByteArray)));
+  connect(m_progress, &QProgressDialog::canceled, m_process, &OBProcess::abort);
+  connect(m_process, &OBProcess::convertFinished, this,
+          &OpenBabel::onHydrogenOperationFinished);
 
   m_progress->setLabelText(
     tr("Running %1…").arg(m_process->obabelExecutable()));
@@ -891,9 +892,9 @@ void OpenBabel::onAddHydrogensPh()
   // Connect process
   disconnect(m_process);
   m_process->disconnect(this);
-  connect(m_progress, SIGNAL(canceled()), m_process, SLOT(abort()));
-  connect(m_process, SIGNAL(convertFinished(QByteArray)),
-          SLOT(onHydrogenOperationFinished(QByteArray)));
+  connect(m_progress, &QProgressDialog::canceled, m_process, &OBProcess::abort);
+  connect(m_process, &OBProcess::convertFinished, this,
+          &OpenBabel::onHydrogenOperationFinished);
 
   m_progress->setLabelText(
     tr("Running %1…").arg(m_process->obabelExecutable()));
@@ -933,9 +934,9 @@ void OpenBabel::onRemoveHydrogens()
   // Connect process
   disconnect(m_process);
   m_process->disconnect(this);
-  connect(m_progress, SIGNAL(canceled()), m_process, SLOT(abort()));
-  connect(m_process, SIGNAL(convertFinished(QByteArray)),
-          SLOT(onHydrogenOperationFinished(QByteArray)));
+  connect(m_progress, &QProgressDialog::canceled, m_process, &OBProcess::abort);
+  connect(m_process, &OBProcess::convertFinished, this,
+          &OpenBabel::onHydrogenOperationFinished);
 
   m_progress->setLabelText(
     tr("Running %1…").arg(m_process->obabelExecutable()));
diff --git a/avogadro/qtplugins/openmminput/openmminput.cpp b/avogadro/qtplugins/openmminput/openmminput.cpp
index 47f63ba449..d0e269cd44 100644
--- a/avogadro/qtplugins/openmminput/openmminput.cpp
+++ b/avogadro/qtplugins/openmminput/openmminput.cpp
@@ -28,7 +28,7 @@ OpenMMInput::OpenMMInput(QObject* parent_)
 {
   m_action->setEnabled(true);
   m_action->setText(tr("&OpenMM Script…"));
-  connect(m_action, SIGNAL(triggered()), SLOT(menuActivated()));
+  connect(m_action, &QAction::triggered, this, &OpenMMInput::menuActivated);
 }
 
 OpenMMInput::~OpenMMInput() {}
diff --git a/avogadro/qtplugins/openmminput/openmminputdialog.cpp b/avogadro/qtplugins/openmminput/openmminputdialog.cpp
index d3a4b986d2..fe6dd69408 100644
--- a/avogadro/qtplugins/openmminput/openmminputdialog.cpp
+++ b/avogadro/qtplugins/openmminput/openmminputdialog.cpp
@@ -71,10 +71,10 @@ OpenMMInputDialog::OpenMMInputDialog(QWidget* parent, Qt::WindowFlags flag)
                                        : ui.inputTopEdit->text());
 
   // Connect the GUI elements to the correct slots
-  connect(ui.jobScriptEdit, SIGNAL(textChanged(QString)), this,
-          SLOT(setScriptName()));
-  connect(ui.inputCoordEdit, SIGNAL(textChanged(QString)), this,
-          SLOT(setInputCoordName()));
+  connect(ui.jobScriptEdit, &QLineEdit::textChanged, this,
+          &OpenMMInputDialog::setScriptName);
+  connect(ui.inputCoordEdit, &QLineEdit::textChanged, this,
+          &OpenMMInputDialog::setInputCoordName);
   connect(ui.forceFieldCombo, SIGNAL(currentIndexChanged(int)), this,
           SLOT(setForceField(int)));
   connect(ui.constraintsCombo, SIGNAL(currentIndexChanged(int)), this,
@@ -87,8 +87,8 @@ OpenMMInputDialog::OpenMMInputDialog(QWidget* parent, Qt::WindowFlags flag)
           SLOT(setIntegratorType(int)));
   connect(ui.barostatCombo, SIGNAL(currentIndexChanged(int)), this,
           SLOT(setBarostatType(int)));
-  connect(ui.inputTopEdit, SIGNAL(textChanged(QString)), this,
-          SLOT(setTopologyName()));
+  connect(ui.inputTopEdit, &QLineEdit::textChanged, this,
+          &OpenMMInputDialog::setTopologyName);
   connect(ui.rigidWaterCombo, SIGNAL(currentIndexChanged(int)), this,
           SLOT(setRigidWater(int)));
   connect(ui.temperatureSpin, SIGNAL(valueChanged(double)), this,
@@ -131,37 +131,41 @@ OpenMMInputDialog::OpenMMInputDialog(QWidget* parent, Qt::WindowFlags flag)
           SLOT(setPlatformType(int)));
   connect(ui.precisionCombo, SIGNAL(currentIndexChanged(int)), this,
           SLOT(setPrecisionType(int)));
-  connect(ui.dcdCheck, SIGNAL(toggled(bool)), this, SLOT(setDCDReporter(bool)));
-  connect(ui.pdbCheck, SIGNAL(toggled(bool)), this, SLOT(setPDBReporter(bool)));
-  connect(ui.stateDataCheck, SIGNAL(toggled(bool)), this,
-          SLOT(setStateDataReporter(bool)));
-
-  connect(ui.stepIndexCheck, SIGNAL(toggled(bool)), this,
-          SLOT(setStepIndexBoolean(bool)));
-  connect(ui.timeCheck, SIGNAL(toggled(bool)), this,
-          SLOT(setTimeBoolean(bool)));
-  connect(ui.speedCheck, SIGNAL(toggled(bool)), this,
-          SLOT(setSpeedBoolean(bool)));
-  connect(ui.progressCheck, SIGNAL(toggled(bool)), this,
-          SLOT(setProgressBoolean(bool)));
-  connect(ui.potentialEnergyCheck, SIGNAL(toggled(bool)), this,
-          SLOT(setPotentialEnergyBoolean(bool)));
-  connect(ui.kineticEnergyCheck, SIGNAL(toggled(bool)), this,
-          SLOT(setKineticEnergyBoolean(bool)));
-  connect(ui.totalEnergyCheck, SIGNAL(toggled(bool)), this,
-          SLOT(setTotalEnergyBoolean(bool)));
-  connect(ui.temperatureCheck, SIGNAL(toggled(bool)), this,
-          SLOT(setTemperatureBoolean(bool)));
-  connect(ui.volumeCheck, SIGNAL(toggled(bool)), this,
-          SLOT(setVolumeBoolean(bool)));
-  connect(ui.densityCheck, SIGNAL(toggled(bool)), this,
-          SLOT(setDensityBoolean(bool)));
-
-  connect(ui.generateButton, SIGNAL(clicked()), this, SLOT(generateClicked()));
-  connect(ui.resetButton, SIGNAL(clicked()), this, SLOT(resetClicked()));
-
-  connect(ui.enableFormButton, SIGNAL(clicked()), this,
-          SLOT(enableFormClicked()));
+  connect(ui.dcdCheck, &QAbstractButton::toggled, this,
+          &OpenMMInputDialog::setDCDReporter);
+  connect(ui.pdbCheck, &QAbstractButton::toggled, this,
+          &OpenMMInputDialog::setPDBReporter);
+  connect(ui.stateDataCheck, &QAbstractButton::toggled, this,
+          &OpenMMInputDialog::setStateDataReporter);
+
+  connect(ui.stepIndexCheck, &QAbstractButton::toggled, this,
+          &OpenMMInputDialog::setStepIndexBoolean);
+  connect(ui.timeCheck, &QAbstractButton::toggled, this,
+          &OpenMMInputDialog::setTimeBoolean);
+  connect(ui.speedCheck, &QAbstractButton::toggled, this,
+          &OpenMMInputDialog::setSpeedBoolean);
+  connect(ui.progressCheck, &QAbstractButton::toggled, this,
+          &OpenMMInputDialog::setProgressBoolean);
+  connect(ui.potentialEnergyCheck, &QAbstractButton::toggled, this,
+          &OpenMMInputDialog::setPotentialEnergyBoolean);
+  connect(ui.kineticEnergyCheck, &QAbstractButton::toggled, this,
+          &OpenMMInputDialog::setKineticEnergyBoolean);
+  connect(ui.totalEnergyCheck, &QAbstractButton::toggled, this,
+          &OpenMMInputDialog::setTotalEnergyBoolean);
+  connect(ui.temperatureCheck, &QAbstractButton::toggled, this,
+          &OpenMMInputDialog::setTemperatureBoolean);
+  connect(ui.volumeCheck, &QAbstractButton::toggled, this,
+          &OpenMMInputDialog::setVolumeBoolean);
+  connect(ui.densityCheck, &QAbstractButton::toggled, this,
+          &OpenMMInputDialog::setDensityBoolean);
+
+  connect(ui.generateButton, &QAbstractButton::clicked, this,
+          &OpenMMInputDialog::generateClicked);
+  connect(ui.resetButton, &QAbstractButton::clicked, this,
+          &OpenMMInputDialog::resetClicked);
+
+  connect(ui.enableFormButton, &QAbstractButton::clicked, this,
+          &OpenMMInputDialog::enableFormClicked);
 
   QSettings settings;
   readSettings(settings);
@@ -214,7 +218,8 @@ void OpenMMInputDialog::updatePreviewText()
   m_jobEdit = new QTextEdit(this);
   m_jobEdit->setObjectName(m_jobFileName);
   m_jobEdit->setFontFamily("monospace");
-  connect(m_jobEdit, SIGNAL(textChanged()), this, SLOT(textEditModified()));
+  connect(m_jobEdit, &QTextEdit::textChanged, this,
+          &OpenMMInputDialog::textEditModified);
   m_jobEdit->setText(generateInputDeck());
   ui.tabWidget->insertTab(jobTabPosition, m_jobEdit, m_jobFileName);
   deckDirty(false);
@@ -408,8 +413,8 @@ void OpenMMInputDialog::generateClicked()
           tr("The input files cannot be written:\n\n%1").arg(errors.first());
         break;
       default: {
-        // If a fatal error occurred, it will be last one in the list. Pop it off
-        // and tell the user that it was the reason we had to stop.
+        // If a fatal error occurred, it will be last one in the list. Pop it
+        // off and tell the user that it was the reason we had to stop.
         QString fatal = errors.last();
         QStringList tmp(errors);
         tmp.pop_back();
@@ -640,7 +645,8 @@ void OpenMMInputDialog::setMolecule(QtGui::Molecule* molecule)
 
   m_molecule = molecule;
   // Update the preview text whenever primitives are changed
-  connect(molecule, SIGNAL(changed(unsigned int)), SLOT(updatePreviewText()));
+  connect(molecule, &QtGui::Molecule::changed, this,
+          &OpenMMInputDialog::updatePreviewText);
   updatePreviewText();
 }
 
@@ -956,8 +962,9 @@ QString OpenMMInputDialog::generateInputDeck()
   scriptStream << "nonbondedMethod="
                << "app." << getNonBondedType(m_nonBondedType) << ",";
   if (m_nonBondedCutoff > 0) {
-    scriptStream << " nonbondedCutoff=" << Qt::fixed << qSetRealNumberPrecision(4)
-                 << m_nonBondedCutoff << "*unit.nanometers,";
+    scriptStream << " nonbondedCutoff=" << Qt::fixed
+                 << qSetRealNumberPrecision(4) << m_nonBondedCutoff
+                 << "*unit.nanometers,";
   }
   if (m_constraintType == None) {
     scriptStream << " constraints=" << getConstraintType(m_constraintType);
@@ -1344,4 +1351,4 @@ void OpenMMInputDialog::writeSettings(QSettings& settings) const
   settings.setValue("openmm/savepath", m_savePath);
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/overlayaxes/overlayaxes.cpp b/avogadro/qtplugins/overlayaxes/overlayaxes.cpp
index 6c47c0084c..ed3351666d 100644
--- a/avogadro/qtplugins/overlayaxes/overlayaxes.cpp
+++ b/avogadro/qtplugins/overlayaxes/overlayaxes.cpp
@@ -11,13 +11,14 @@
 #include <avogadro/rendering/groupnode.h>
 #include <avogadro/rendering/meshgeometry.h>
 #include <avogadro/rendering/scene.h>
+
 #include <avogadro/qtopengl/glwidget.h>
 
 #include <avogadro/core/array.h>
 #include <avogadro/core/vector.h>
 
-#include <QSettings>
 #include <QAction>
+#include <QSettings>
 
 #include <Eigen/Geometry>
 
@@ -236,7 +237,7 @@ OverlayAxes::OverlayAxes(QObject* p)
     m_render(new RenderImpl), m_glWidget(nullptr),
     m_axesAction(new QAction(tr("Reference Axes"), this))
 {
-  connect(m_axesAction, SIGNAL(triggered()), SLOT(processAxes()));
+  connect(m_axesAction, &QAction::triggered, this, &OverlayAxes::processAxes);
 
   QSettings settings;
   m_enabled = settings.value("overlayAxes/enabled", true).toBool();
@@ -325,4 +326,4 @@ void OverlayAxes::setScene(Rendering::Scene* scene)
   }
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/playertool/playertool.cpp b/avogadro/qtplugins/playertool/playertool.cpp
index 9345bf06e4..3ced6199fe 100644
--- a/avogadro/qtplugins/playertool/playertool.cpp
+++ b/avogadro/qtplugins/playertool/playertool.cpp
@@ -69,17 +69,17 @@ QWidget* PlayerTool::toolWidget() const
     auto* controls = new QHBoxLayout;
     controls->addStretch(1);
     auto* leftButton = new QPushButton("<");
-    connect(leftButton, SIGNAL(clicked()), SLOT(back()));
+    connect(leftButton, &QAbstractButton::clicked, this, &PlayerTool::back);
     controls->addWidget(leftButton);
     playButton = new QPushButton(tr("Play"));
-    connect(playButton, SIGNAL(clicked()), SLOT(play()));
+    connect(playButton, &QAbstractButton::clicked, this, &PlayerTool::play);
     controls->addWidget(playButton);
     stopButton = new QPushButton(tr("Stop"));
-    connect(stopButton, SIGNAL(clicked()), SLOT(stop()));
+    connect(stopButton, &QAbstractButton::clicked, this, &PlayerTool::stop);
     controls->addWidget(stopButton);
     stopButton->setEnabled(false);
     auto* rightButton = new QPushButton(">");
-    connect(rightButton, SIGNAL(clicked()), SLOT(forward()));
+    connect(rightButton, &QAbstractButton::clicked, this, &PlayerTool::forward);
     controls->addWidget(rightButton);
     controls->addStretch(1);
     layout->addLayout(controls);
@@ -99,8 +99,8 @@ QWidget* PlayerTool::toolWidget() const
     m_slider = new QSlider(Qt::Horizontal);
     m_slider->setMinimum(0);
     m_slider->setTickInterval(1);
-    connect(m_slider, SIGNAL(valueChanged(int)),
-            SLOT(sliderPositionChanged(int)));
+    connect(m_slider, &QAbstractSlider::valueChanged, this,
+            &PlayerTool::sliderPositionChanged);
     sliderLayout->addWidget(m_slider);
     layout->addLayout(sliderLayout);
     if (m_molecule->coordinate3dCount() > 1)
@@ -142,7 +142,8 @@ QWidget* PlayerTool::toolWidget() const
     auto* recordLayout = new QHBoxLayout;
     recordLayout->addStretch(1);
     auto* recordButton = new QPushButton(tr("Record Movie…"));
-    connect(recordButton, SIGNAL(clicked()), SLOT(recordMovie()));
+    connect(recordButton, &QAbstractButton::clicked, this,
+            &PlayerTool::recordMovie);
     recordLayout->addWidget(recordButton);
     recordLayout->addStretch(1);
     layout->addLayout(recordLayout);
diff --git a/avogadro/qtplugins/plugindownloader/downloaderwidget.cpp b/avogadro/qtplugins/plugindownloader/downloaderwidget.cpp
index c8d539c5e8..cf90d6bc0a 100644
--- a/avogadro/qtplugins/plugindownloader/downloaderwidget.cpp
+++ b/avogadro/qtplugins/plugindownloader/downloaderwidget.cpp
@@ -52,10 +52,10 @@ DownloaderWidget::DownloaderWidget(QWidget* parent)
   // enable links in the readme to open an external browser
   m_ui->readmeBrowser->setOpenExternalLinks(true);
 
-  connect(m_ui->downloadButton, SIGNAL(clicked(bool)), this,
-          SLOT(getCheckedRepos()));
-  connect(m_ui->repoTable, SIGNAL(cellClicked(int, int)), this,
-          SLOT(downloadREADME(int, int)));
+  connect(m_ui->downloadButton, &QAbstractButton::clicked, this,
+          &DownloaderWidget::getCheckedRepos);
+  connect(m_ui->repoTable, &QTableWidget::cellClicked, this,
+          &DownloaderWidget::downloadREADME);
 
   m_ui->repoTable->setColumnCount(4);
   m_ui->repoTable->setSelectionBehavior(QAbstractItemView::SelectRows);
@@ -84,7 +84,8 @@ void DownloaderWidget::getRepoData(QString url)
   setRawHeaders(&request);
   request.setUrl(url); // Set the url
   m_reply = m_NetworkAccessManager->get(request);
-  connect(m_reply, SIGNAL(finished()), this, SLOT(updateRepoData()));
+  connect(m_reply, &QNetworkReply::finished, this,
+          &DownloaderWidget::updateRepoData);
 }
 
 // Process the master plugin.json hosted on Avogadro.cc
@@ -187,7 +188,8 @@ void DownloaderWidget::downloadREADME(int row, int col)
   setRawHeaders(&request);
   request.setUrl(url); // Set the url
   m_reply = m_NetworkAccessManager->get(request);
-  connect(m_reply, SIGNAL(finished()), this, SLOT(showREADME()));
+  connect(m_reply, &QNetworkReply::finished, this,
+          &DownloaderWidget::showREADME);
 }
 
 // display README when the user clicks a row
@@ -282,7 +284,8 @@ void DownloaderWidget::downloadNext()
     setRawHeaders(&request);
     request.setUrl(url); // Set the url
     m_reply = m_NetworkAccessManager->get(request);
-    connect(m_reply, SIGNAL(finished()), this, SLOT(handleRedirect()));
+    connect(m_reply, &QNetworkReply::finished, this,
+            &DownloaderWidget::handleRedirect);
   }
 }
 
@@ -347,7 +350,8 @@ void DownloaderWidget::handleRedirect()
       request.setUrl(_urlRedirectedTo); // Set the url
       m_reply = m_NetworkAccessManager->get(request);
       // Now we have the actual zip and can extract it
-      connect(m_reply, SIGNAL(finished()), this, SLOT(unzipPlugin()));
+      connect(m_reply, &QNetworkReply::finished, this,
+              &DownloaderWidget::unzipPlugin);
     } else if (statusCode == 200) {
       // Normal success response
       unzipPlugin();
diff --git a/avogadro/qtplugins/plugindownloader/plugindownloader.cpp b/avogadro/qtplugins/plugindownloader/plugindownloader.cpp
index f5f797a803..3c4415d4e7 100644
--- a/avogadro/qtplugins/plugindownloader/plugindownloader.cpp
+++ b/avogadro/qtplugins/plugindownloader/plugindownloader.cpp
@@ -26,7 +26,8 @@ PluginDownloader::PluginDownloader(QObject* parent_)
   m_downloadAction->setEnabled(true);
   m_downloadAction->setText(tr("Download Plugins…"));
   m_downloadAction->setProperty("menu priority", 520);
-  connect(m_downloadAction, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(m_downloadAction, &QAction::triggered, this,
+          &PluginDownloader::showDialog);
 }
 
 PluginDownloader::~PluginDownloader() = default;
diff --git a/avogadro/qtplugins/ply/ply.cpp b/avogadro/qtplugins/ply/ply.cpp
index 9b07a0d146..a8af1786eb 100644
--- a/avogadro/qtplugins/ply/ply.cpp
+++ b/avogadro/qtplugins/ply/ply.cpp
@@ -10,11 +10,11 @@
 #include <avogadro/rendering/plyvisitor.h>
 #include <avogadro/rendering/scene.h>
 
+#include <QAction>
 #include <QtCore/QTextStream>
 #include <QtGui/QClipboard>
 #include <QtGui/QIcon>
 #include <QtGui/QKeySequence>
-#include <QAction>
 #include <QtWidgets/QApplication>
 #include <QtWidgets/QFileDialog>
 #include <QtWidgets/QMessageBox>
@@ -28,12 +28,10 @@ PLY::PLY(QObject* p)
   : Avogadro::QtGui::ExtensionPlugin(p), m_molecule(nullptr), m_scene(nullptr),
     m_camera(nullptr), m_action(new QAction(tr("PLY Render…"), this))
 {
-  connect(m_action, SIGNAL(triggered()), SLOT(render()));
+  connect(m_action, &QAction::triggered, this, &PLY::render);
 }
 
-PLY::~PLY()
-{
-}
+PLY::~PLY() {}
 
 QList<QAction*> PLY::actions() const
 {
@@ -82,4 +80,4 @@ void PLY::render()
   file.close();
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/povray/povray.cpp b/avogadro/qtplugins/povray/povray.cpp
index d84e683538..a0c13c405e 100644
--- a/avogadro/qtplugins/povray/povray.cpp
+++ b/avogadro/qtplugins/povray/povray.cpp
@@ -10,11 +10,11 @@
 #include <avogadro/rendering/povrayvisitor.h>
 #include <avogadro/rendering/scene.h>
 
+#include <QAction>
 #include <QtCore/QTextStream>
 #include <QtGui/QClipboard>
 #include <QtGui/QIcon>
 #include <QtGui/QKeySequence>
-#include <QAction>
 #include <QtWidgets/QApplication>
 #include <QtWidgets/QFileDialog>
 #include <QtWidgets/QMessageBox>
@@ -28,12 +28,10 @@ POVRay::POVRay(QObject* p)
   : Avogadro::QtGui::ExtensionPlugin(p), m_molecule(nullptr), m_scene(nullptr),
     m_camera(nullptr), m_action(new QAction(tr("POV-Ray Render…"), this))
 {
-  connect(m_action, SIGNAL(triggered()), SLOT(render()));
+  connect(m_action, &QAction::triggered, this, &POVRay::render);
 }
 
-POVRay::~POVRay()
-{
-}
+POVRay::~POVRay() {}
 
 QList<QAction*> POVRay::actions() const
 {
@@ -82,4 +80,4 @@ void POVRay::render()
   file.close();
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/propertytables/propertymodel.cpp b/avogadro/qtplugins/propertytables/propertymodel.cpp
index e19ea0dccf..0c6b42140b 100644
--- a/avogadro/qtplugins/propertytables/propertymodel.cpp
+++ b/avogadro/qtplugins/propertytables/propertymodel.cpp
@@ -921,8 +921,8 @@ void PropertyModel::setMolecule(QtGui::Molecule* molecule)
 
     updateCache();
 
-    connect(m_molecule, SIGNAL(changed(unsigned int)), this,
-            SLOT(updateTable(unsigned int)));
+    connect(m_molecule, &QtGui::Molecule::changed, this,
+            &PropertyModel::updateTable);
   }
 }
 
diff --git a/avogadro/qtplugins/propertytables/propertytables.cpp b/avogadro/qtplugins/propertytables/propertytables.cpp
index 430527f0eb..4df2a1f746 100644
--- a/avogadro/qtplugins/propertytables/propertytables.cpp
+++ b/avogadro/qtplugins/propertytables/propertytables.cpp
@@ -27,28 +27,28 @@ PropertyTables::PropertyTables(QObject* parent_)
   action->setText(tr("Atom Properties…"));
   action->setData(PropertyType::AtomType);
   action->setProperty("menu priority", 880);
-  connect(action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(action, &QAction::triggered, this, &PropertyTables::showDialog);
   m_actions.append(action);
 
   action = new QAction(this);
   action->setText(tr("Bond Properties…"));
   action->setData(PropertyType::BondType);
   action->setProperty("menu priority", 870);
-  connect(action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(action, &QAction::triggered, this, &PropertyTables::showDialog);
   m_actions.append(action);
 
   action = new QAction(this);
   action->setText(tr("Angle Properties…"));
   action->setData(PropertyType::AngleType);
   action->setProperty("menu priority", 860);
-  connect(action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(action, &QAction::triggered, this, &PropertyTables::showDialog);
   m_actions.append(action);
 
   action = new QAction(this);
   action->setText(tr("Torsion Properties…"));
   action->setData(PropertyType::TorsionType);
   action->setProperty("menu priority", 850);
-  connect(action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(action, &QAction::triggered, this, &PropertyTables::showDialog);
   m_actions.append(action);
 
   action = new QAction(this);
@@ -56,7 +56,7 @@ PropertyTables::PropertyTables(QObject* parent_)
   action->setData(PropertyType::ResidueType);
   action->setProperty("menu priority", 840);
   action->setEnabled(false); // changed by molecule
-  connect(action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(action, &QAction::triggered, this, &PropertyTables::showDialog);
   m_actions.append(action);
 
   action = new QAction(this);
@@ -64,7 +64,7 @@ PropertyTables::PropertyTables(QObject* parent_)
   action->setData(PropertyType::ConformerType);
   action->setProperty("menu priority", 830);
   action->setEnabled(false); // changed by molecule
-  connect(action, SIGNAL(triggered()), SLOT(showDialog()));
+  connect(action, &QAction::triggered, this, &PropertyTables::showDialog);
   m_actions.append(action);
 }
 
@@ -96,7 +96,8 @@ void PropertyTables::setMolecule(QtGui::Molecule* mol)
   updateActions();
 
   // update if the molecule changes
-  connect(m_molecule, SIGNAL(changed(unsigned int)), SLOT(updateActions()));
+  connect(m_molecule, &QtGui::Molecule::changed, this,
+          &PropertyTables::updateActions);
 }
 
 void PropertyTables::updateActions()
diff --git a/avogadro/qtplugins/propertytables/propertyview.cpp b/avogadro/qtplugins/propertytables/propertyview.cpp
index f84e8543bc..9383815d1f 100644
--- a/avogadro/qtplugins/propertytables/propertyview.cpp
+++ b/avogadro/qtplugins/propertytables/propertyview.cpp
@@ -36,7 +36,7 @@ namespace Avogadro {
 using QtGui::Molecule;
 
 PropertyView::PropertyView(PropertyType type, QWidget* parent)
-  : QTableView(parent), m_molecule(nullptr), m_type(type), m_model(nullptr)
+  : QTableView(parent), m_type(type), m_molecule(nullptr), m_model(nullptr)
 {
   QString title;
   switch (type) {
diff --git a/avogadro/qtplugins/qtaim/qtaimcriticalpointlocator.cpp b/avogadro/qtplugins/qtaim/qtaimcriticalpointlocator.cpp
index 55cc2a1b5b..41f011edc3 100644
--- a/avogadro/qtplugins/qtaim/qtaimcriticalpointlocator.cpp
+++ b/avogadro/qtplugins/qtaim/qtaimcriticalpointlocator.cpp
@@ -391,12 +391,14 @@ void QTAIMCriticalPointLocator::locateNuclearCriticalPoints()
   dialog.setLabelText(QString("Nuclear Critical Points Search"));
 
   QFutureWatcher<void> futureWatcher;
-  QObject::connect(&futureWatcher, SIGNAL(finished()), &dialog, SLOT(reset()));
-  QObject::connect(&dialog, SIGNAL(canceled()), &futureWatcher, SLOT(cancel()));
-  QObject::connect(&futureWatcher, SIGNAL(progressRangeChanged(int, int)),
-                   &dialog, SLOT(setRange(int, int)));
-  QObject::connect(&futureWatcher, SIGNAL(progressValueChanged(int)), &dialog,
-                   SLOT(setValue(int)));
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::finished, &dialog,
+                   &QProgressDialog::reset);
+  QObject::connect(&dialog, &QProgressDialog::canceled, &futureWatcher,
+                   &QFutureWatcherBase::cancel);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressRangeChanged,
+                   &dialog, &QProgressDialog::setRange);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressValueChanged,
+                   &dialog, &QProgressDialog::setValue);
 
   QFuture<QList<QVariant>> future =
     QtConcurrent::mapped(inputList, QTAIMLocateNuclearCriticalPoint);
@@ -414,11 +416,9 @@ void QTAIMCriticalPointLocator::locateNuclearCriticalPoints()
   QFile file;
   file.remove(tempFileName);
 
-  for (const auto & n : results) {
+  for (const auto& n : results) {
     if (n.at(0).toBool()) {
-      QVector3D result(n.at(1).toReal(),
-                       n.at(2).toReal(),
-                       n.at(3).toReal());
+      QVector3D result(n.at(1).toReal(), n.at(2).toReal(), n.at(3).toReal());
 
       m_nuclearCriticalPoints.append(result);
     }
@@ -490,12 +490,14 @@ void QTAIMCriticalPointLocator::locateBondCriticalPoints()
   dialog.setLabelText(QString("Bond Critical Points Search"));
 
   QFutureWatcher<void> futureWatcher;
-  QObject::connect(&futureWatcher, SIGNAL(finished()), &dialog, SLOT(reset()));
-  QObject::connect(&dialog, SIGNAL(canceled()), &futureWatcher, SLOT(cancel()));
-  QObject::connect(&futureWatcher, SIGNAL(progressRangeChanged(int, int)),
-                   &dialog, SLOT(setRange(int, int)));
-  QObject::connect(&futureWatcher, SIGNAL(progressValueChanged(int)), &dialog,
-                   SLOT(setValue(int)));
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::finished, &dialog,
+                   &QProgressDialog::reset);
+  QObject::connect(&dialog, &QProgressDialog::canceled, &futureWatcher,
+                   &QFutureWatcherBase::cancel);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressRangeChanged,
+                   &dialog, &QProgressDialog::setRange);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressValueChanged,
+                   &dialog, &QProgressDialog::setValue);
 
   QFuture<QList<QVariant>> future =
     QtConcurrent::mapped(inputList, QTAIMLocateBondCriticalPoint);
@@ -637,12 +639,14 @@ void QTAIMCriticalPointLocator::locateElectronDensitySources()
   dialog.setLabelText(QString("Electron Density Sources Search"));
 
   QFutureWatcher<void> futureWatcher;
-  QObject::connect(&futureWatcher, SIGNAL(finished()), &dialog, SLOT(reset()));
-  QObject::connect(&dialog, SIGNAL(canceled()), &futureWatcher, SLOT(cancel()));
-  QObject::connect(&futureWatcher, SIGNAL(progressRangeChanged(int, int)),
-                   &dialog, SLOT(setRange(int, int)));
-  QObject::connect(&futureWatcher, SIGNAL(progressValueChanged(int)), &dialog,
-                   SLOT(setValue(int)));
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::finished, &dialog,
+                   &QProgressDialog::reset);
+  QObject::connect(&dialog, &QProgressDialog::canceled, &futureWatcher,
+                   &QFutureWatcherBase::cancel);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressRangeChanged,
+                   &dialog, &QProgressDialog::setRange);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressValueChanged,
+                   &dialog, &QProgressDialog::setValue);
 
   QFuture<QList<QVariant>> future =
     QtConcurrent::mapped(inputList, QTAIMLocateElectronDensitySource);
@@ -660,7 +664,7 @@ void QTAIMCriticalPointLocator::locateElectronDensitySources()
   QFile file;
   file.remove(tempFileName);
 
-  for (const auto & n : results) {
+  for (const auto& n : results) {
     if (n.at(0).toBool()) {
       qreal x = n.at(1).toReal();
       qreal y = n.at(2).toReal();
@@ -782,12 +786,14 @@ void QTAIMCriticalPointLocator::locateElectronDensitySinks()
   dialog.setLabelText(QString("Electron Density Sinks Search"));
 
   QFutureWatcher<void> futureWatcher;
-  QObject::connect(&futureWatcher, SIGNAL(finished()), &dialog, SLOT(reset()));
-  QObject::connect(&dialog, SIGNAL(canceled()), &futureWatcher, SLOT(cancel()));
-  QObject::connect(&futureWatcher, SIGNAL(progressRangeChanged(int, int)),
-                   &dialog, SLOT(setRange(int, int)));
-  QObject::connect(&futureWatcher, SIGNAL(progressValueChanged(int)), &dialog,
-                   SLOT(setValue(int)));
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::finished, &dialog,
+                   &QProgressDialog::reset);
+  QObject::connect(&dialog, &QProgressDialog::canceled, &futureWatcher,
+                   &QFutureWatcherBase::cancel);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressRangeChanged,
+                   &dialog, &QProgressDialog::setRange);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressValueChanged,
+                   &dialog, &QProgressDialog::setValue);
 
   QFuture<QList<QVariant>> future =
     QtConcurrent::mapped(inputList, QTAIMLocateElectronDensitySink);
@@ -805,7 +811,7 @@ void QTAIMCriticalPointLocator::locateElectronDensitySinks()
   QFile file;
   file.remove(tempFileName);
 
-  for (const auto & n : results) {
+  for (const auto& n : results) {
     if (n.at(0).toBool()) {
       qreal x = n.at(1).toReal();
       qreal y = n.at(2).toReal();
@@ -857,4 +863,4 @@ QString QTAIMCriticalPointLocator::temporaryFileName()
   return tempFileName;
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/qtaim/qtaimcubature.cpp b/avogadro/qtplugins/qtaim/qtaimcubature.cpp
index 130f9c1852..2309bb2f49 100644
--- a/avogadro/qtplugins/qtaim/qtaimcubature.cpp
+++ b/avogadro/qtplugins/qtaim/qtaimcubature.cpp
@@ -705,10 +705,14 @@ static int rule15gauss_evalError(rule* r, unsigned int fdim, integrand_v f,
   const unsigned int n = 8;
   const double xgk[8] = {
     /* abscissae of the 15-point kronrod rule */
-    0.991455371120812639206854697526329, 0.949107912342758524526189684047851,
-    0.864864423359769072789712788640926, 0.741531185599394439863864773280788,
-    0.586087235467691130294144838258730, 0.405845151377397166906606412076961,
-    0.207784955007898467600689403773245, 0.000000000000000000000000000000000
+    0.991455371120812639206854697526329,
+    0.949107912342758524526189684047851,
+    0.864864423359769072789712788640926,
+    0.741531185599394439863864773280788,
+    0.586087235467691130294144838258730,
+    0.405845151377397166906606412076961,
+    0.207784955007898467600689403773245,
+    0.000000000000000000000000000000000
     /* xgk[1], xgk[3], ... abscissae of the 7-point gauss rule.
        xgk[0], xgk[2], ... to optimally extend the 7-point gauss rule */
   };
@@ -1279,7 +1283,7 @@ QList<QVariant> QTAIMEvaluateProperty(QList<QVariant> variantList)
     ode.setBetaSpheres(betaSpheres);
 
     QVector3D endpoint = ode.integrate(QVector3D(x0, y0, z0));
-// QList<QVector3D> path=ode.path();
+    // QList<QVector3D> path=ode.path();
 
 #define HUGE_REAL_NUMBER 1.e20
     qreal smallestDistance = HUGE_REAL_NUMBER;
@@ -1408,12 +1412,14 @@ void property_v(unsigned int /* ndim */, unsigned int npts, const double* xyz,
   dialog.setLabelText(QString("Atomic Basin Integration"));
 
   QFutureWatcher<void> futureWatcher;
-  QObject::connect(&futureWatcher, SIGNAL(finished()), &dialog, SLOT(reset()));
-  QObject::connect(&dialog, SIGNAL(canceled()), &futureWatcher, SLOT(cancel()));
-  QObject::connect(&futureWatcher, SIGNAL(progressRangeChanged(int, int)),
-                   &dialog, SLOT(setRange(int, int)));
-  QObject::connect(&futureWatcher, SIGNAL(progressValueChanged(int)), &dialog,
-                   SLOT(setValue(int)));
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::finished, &dialog,
+                   &QProgressDialog::reset);
+  QObject::connect(&dialog, &QProgressDialog::canceled, &futureWatcher,
+                   &QFutureWatcherBase::cancel);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressRangeChanged,
+                   &dialog, &QProgressDialog::setRange);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressValueChanged,
+                   &dialog, &QProgressDialog::setValue);
 
   QFuture<QList<QVariant>> future =
     QtConcurrent::mapped(inputList, QTAIMEvaluateProperty);
@@ -1552,7 +1558,7 @@ QList<QVariant> QTAIMEvaluatePropertyRTP(QList<QVariant> variantList)
     ode.setBetaSpheres(betaSpheres);
 
     QVector3D endpoint = ode.integrate(QVector3D(x0, y0, z0));
-// QList<QVector3D> path=ode.path();
+    // QList<QVector3D> path=ode.path();
 
 #define HUGE_REAL_NUMBER 1.e20
     qreal smallestDistance = HUGE_REAL_NUMBER;
@@ -1590,7 +1596,7 @@ QList<QVariant> QTAIMEvaluatePropertyRTP(QList<QVariant> variantList)
             r0 * r0 * sin(t0) *
             eval.electronDensity(Eigen::Vector3d(x0, y0, z0))
 
-              );
+          );
         } else {
           qDebug() << "mode not defined";
           qreal zero = 0.0;
@@ -1688,12 +1694,14 @@ void property_v_rtp(unsigned int /* ndim */, unsigned int npts,
   dialog.setLabelText(QString("Atomic Basin Integration"));
 
   QFutureWatcher<void> futureWatcher;
-  QObject::connect(&futureWatcher, SIGNAL(finished()), &dialog, SLOT(reset()));
-  QObject::connect(&dialog, SIGNAL(canceled()), &futureWatcher, SLOT(cancel()));
-  QObject::connect(&futureWatcher, SIGNAL(progressRangeChanged(int, int)),
-                   &dialog, SLOT(setRange(int, int)));
-  QObject::connect(&futureWatcher, SIGNAL(progressValueChanged(int)), &dialog,
-                   SLOT(setValue(int)));
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::finished, &dialog,
+                   &QProgressDialog::reset);
+  QObject::connect(&dialog, &QProgressDialog::canceled, &futureWatcher,
+                   &QFutureWatcherBase::cancel);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressRangeChanged,
+                   &dialog, &QProgressDialog::setRange);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressValueChanged,
+                   &dialog, &QProgressDialog::setValue);
 
   QFuture<QList<QVariant>> future =
     QtConcurrent::mapped(inputList, QTAIMEvaluatePropertyRTP);
@@ -2168,12 +2176,14 @@ void property_v_tp(unsigned int /* ndim */, unsigned int npts,
   dialog.setLabelText(QString("Atomic Basin Integration"));
 
   QFutureWatcher<void> futureWatcher;
-  QObject::connect(&futureWatcher, SIGNAL(finished()), &dialog, SLOT(reset()));
-  QObject::connect(&dialog, SIGNAL(canceled()), &futureWatcher, SLOT(cancel()));
-  QObject::connect(&futureWatcher, SIGNAL(progressRangeChanged(int, int)),
-                   &dialog, SLOT(setRange(int, int)));
-  QObject::connect(&futureWatcher, SIGNAL(progressValueChanged(int)), &dialog,
-                   SLOT(setValue(int)));
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::finished, &dialog,
+                   &QProgressDialog::reset);
+  QObject::connect(&dialog, &QProgressDialog::canceled, &futureWatcher,
+                   &QFutureWatcherBase::cancel);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressRangeChanged,
+                   &dialog, &QProgressDialog::setRange);
+  QObject::connect(&futureWatcher, &QFutureWatcherBase::progressValueChanged,
+                   &dialog, &QProgressDialog::setValue);
 
   QFuture<QList<QVariant>> future =
     QtConcurrent::mapped(inputList, QTAIMEvaluatePropertyTP);
@@ -2386,4 +2396,4 @@ QString QTAIMCubature::temporaryFileName()
   return tempFileName;
 }
 
-} // end namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/qtaim/qtaimextension.cpp b/avogadro/qtplugins/qtaim/qtaimextension.cpp
index 1fb5714a48..aedddbcf55 100644
--- a/avogadro/qtplugins/qtaim/qtaimextension.cpp
+++ b/avogadro/qtplugins/qtaim/qtaimextension.cpp
@@ -41,21 +41,21 @@ QTAIMExtension::QTAIMExtension(QObject* aParent)
   action->setText(tr("Molecular Graph…"));
   m_actions.append(action);
   action->setData(FirstAction);
-  connect(action, SIGNAL(triggered()), SLOT(triggered()));
+  connect(action, &QAction::triggered, this, &QTAIMExtension::triggered);
 
   // create an action for our second action
   action = new QAction(this);
   action->setText(tr("Molecular Graph with Lone Pairs…"));
   m_actions.append(action);
   action->setData(SecondAction);
-  connect(action, SIGNAL(triggered()), SLOT(triggered()));
+  connect(action, &QAction::triggered, this, &QTAIMExtension::triggered);
 
   // create an action for our third action
   action = new QAction(this);
   action->setText(tr("Atomic Charge…"));
   m_actions.append(action);
   action->setData(ThirdAction);
-  connect(action, SIGNAL(triggered()), SLOT(triggered()));
+  connect(action, &QAction::triggered, this, &QTAIMExtension::triggered);
 }
 
 QList<QAction*> QTAIMExtension::actions() const
@@ -260,12 +260,9 @@ void QTAIMExtension::triggered()
 
                 bondPathSegmentStartIndexVariantList.append(bpCtr);
                 for (auto j : bondPathList.at(bondPair)) {
-                  x =
-                    j.x() * convertBohrToAngstrom;
-                  y =
-                    j.y() * convertBohrToAngstrom;
-                  z =
-                    j.z() * convertBohrToAngstrom;
+                  x = j.x() * convertBohrToAngstrom;
+                  y = j.y() * convertBohrToAngstrom;
+                  z = j.z() * convertBohrToAngstrom;
 
                   xBondPathsVariantList.append(x);
                   yBondPathsVariantList.append(y);
@@ -435,12 +432,9 @@ void QTAIMExtension::triggered()
 
                 bondPathSegmentStartIndexVariantList.append(bpCtr);
                 for (auto j : bondPathList.at(bondPair)) {
-                  x =
-                    j.x() * convertBohrToAngstrom;
-                  y =
-                    j.y() * convertBohrToAngstrom;
-                  z =
-                    j.z() * convertBohrToAngstrom;
+                  x = j.x() * convertBohrToAngstrom;
+                  y = j.y() * convertBohrToAngstrom;
+                  z = j.z() * convertBohrToAngstrom;
 
                   xBondPathsVariantList.append(x);
                   yBondPathsVariantList.append(y);
@@ -646,12 +640,9 @@ void QTAIMExtension::triggered()
 
                   bondPathSegmentStartIndexVariantList.append(bpCtr);
                   for (auto j : bondPathList.at(bondPair)) {
-                    x = j.x() *
-                        convertBohrToAngstrom;
-                    y = j.y() *
-                        convertBohrToAngstrom;
-                    z = j.z() *
-                        convertBohrToAngstrom;
+                    x = j.x() * convertBohrToAngstrom;
+                    y = j.y() * convertBohrToAngstrom;
+                    z = j.z() * convertBohrToAngstrom;
 
                     xBondPathsVariantList.append(x);
                     yBondPathsVariantList.append(y);
@@ -727,4 +718,4 @@ void QTAIMExtension::triggered()
   emit requestActiveDisplayTypes(QStringList() << "QTAIMScenePlugin");
 }
 
-} // end namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/quantuminput/quantuminput.cpp b/avogadro/qtplugins/quantuminput/quantuminput.cpp
index 2c15d79a78..f3b5bd17c9 100644
--- a/avogadro/qtplugins/quantuminput/quantuminput.cpp
+++ b/avogadro/qtplugins/quantuminput/quantuminput.cpp
@@ -131,8 +131,8 @@ void QuantumInput::menuActivated()
 
   if (!dlg) {
     dlg = new InputGeneratorDialog(scriptFileName, theParent);
-    connect(&dlg->widget(), SIGNAL(openJobOutput(const MoleQueue::JobObject&)),
-            this, SLOT(openJobOutput(const MoleQueue::JobObject&)));
+    connect(&dlg->widget(), &MoleQueue::InputGeneratorWidget::openJobOutput,
+            this, &QuantumInput::openJobOutput);
     m_dialogs.insert(scriptFileName, dlg);
   }
   dlg->setMolecule(m_molecule);
@@ -173,7 +173,7 @@ void QuantumInput::addAction(const QString& label,
   auto* action = new QAction(label, this);
   action->setData(scriptFilePath);
   action->setEnabled(true);
-  connect(action, SIGNAL(triggered()), SLOT(menuActivated()));
+  connect(action, &QAction::triggered, this, &QuantumInput::menuActivated);
   m_actions << action;
 }
 
diff --git a/avogadro/qtplugins/resetview/resetview.cpp b/avogadro/qtplugins/resetview/resetview.cpp
index c191959fa9..e3b1d3739d 100644
--- a/avogadro/qtplugins/resetview/resetview.cpp
+++ b/avogadro/qtplugins/resetview/resetview.cpp
@@ -41,8 +41,9 @@ ResetView::ResetView(QObject* parent_)
   m_centerAction->setProperty("menu priority", 210);
   m_viewToAxesAction->setProperty("menu priority", 200);
 
-  connect(m_centerAction, SIGNAL(triggered()), SLOT(centerView()));
-  connect(m_viewToAxesAction, SIGNAL(triggered()), SLOT(alignToAxes()));
+  connect(m_centerAction, &QAction::triggered, this, &ResetView::centerView);
+  connect(m_viewToAxesAction, &QAction::triggered, this,
+          &ResetView::alignToAxes);
 }
 
 ResetView::~ResetView() {}
diff --git a/avogadro/qtplugins/scriptcharges/scriptchargemodel.cpp b/avogadro/qtplugins/scriptcharges/scriptchargemodel.cpp
index 6802ef8e65..a84a8f68e7 100644
--- a/avogadro/qtplugins/scriptcharges/scriptchargemodel.cpp
+++ b/avogadro/qtplugins/scriptcharges/scriptchargemodel.cpp
@@ -27,8 +27,9 @@
 namespace Avogadro::QtPlugins {
 
 ScriptChargeModel::ScriptChargeModel(const QString& scriptFileName_)
-  : m_interpreter(new QtGui::PythonScript(scriptFileName_)), m_valid(false),
-    m_partialCharges(false), m_electrostatics(false), m_inputFormat(NotUsed)
+  : m_interpreter(new QtGui::PythonScript(scriptFileName_)),
+    m_inputFormat(NotUsed), m_valid(false), m_partialCharges(false),
+    m_electrostatics(false)
 {
   m_elements.reset();
   readMetaData();
diff --git a/avogadro/qtplugins/select/select.cpp b/avogadro/qtplugins/select/select.cpp
index b93185f001..4dc6ee7233 100644
--- a/avogadro/qtplugins/select/select.cpp
+++ b/avogadro/qtplugins/select/select.cpp
@@ -31,13 +31,13 @@ Select::Select(QObject* parent_)
   auto* action = new QAction(tr("Select All"), this);
   action->setShortcut(QKeySequence("Ctrl+A"));
   action->setProperty("menu priority", 990);
-  connect(action, SIGNAL(triggered()), SLOT(selectAll()));
+  connect(action, &QAction::triggered, this, &Select::selectAll);
   m_actions.append(action);
 
   action = new QAction(tr("Select None"), this);
   action->setShortcut(QKeySequence("Ctrl+Shift+A"));
   action->setProperty("menu priority", 980);
-  connect(action, SIGNAL(triggered()), SLOT(selectNone()));
+  connect(action, &QAction::triggered, this, &Select::selectNone);
   m_actions.append(action);
 
   action = new QAction(this);
@@ -47,7 +47,7 @@ Select::Select(QObject* parent_)
 
   action = new QAction(tr("Invert Selection"), this);
   action->setProperty("menu priority", 890);
-  connect(action, SIGNAL(triggered()), SLOT(invertSelection()));
+  connect(action, &QAction::triggered, this, &Select::invertSelection);
   m_actions.append(action);
 
   action = new QAction(tr("Select by Element…"), this);
@@ -57,27 +57,27 @@ Select::Select(QObject* parent_)
 
   action = new QAction(tr("Select by Atom Index…"), this);
   action->setProperty("menu priority", 870);
-  connect(action, SIGNAL(triggered()), SLOT(selectAtomIndex()));
+  connect(action, &QAction::triggered, this, &Select::selectAtomIndex);
   m_actions.append(action);
 
   action = new QAction(tr("Select by Residue…"), this);
   action->setProperty("menu priority", 860);
-  connect(action, SIGNAL(triggered()), SLOT(selectResidue()));
+  connect(action, &QAction::triggered, this, &Select::selectResidue);
   m_actions.append(action);
 
   action = new QAction(tr("Select Backbone Atoms…"), this);
   action->setProperty("menu priority", 858);
-  connect(action, SIGNAL(triggered()), SLOT(selectBackboneAtoms()));
+  connect(action, &QAction::triggered, this, &Select::selectBackboneAtoms);
   m_actions.append(action);
 
   action = new QAction(tr("Select Sidechain Atoms…"), this);
   action->setProperty("menu priority", 855);
-  connect(action, SIGNAL(triggered()), SLOT(selectSidechainAtoms()));
+  connect(action, &QAction::triggered, this, &Select::selectSidechainAtoms);
   m_actions.append(action);
 
   action = new QAction(tr("Select Water"), this);
   action->setProperty("menu priority", 850);
-  connect(action, SIGNAL(triggered()), SLOT(selectWater()));
+  connect(action, &QAction::triggered, this, &Select::selectWater);
   m_actions.append(action);
 
   action = new QAction(this);
@@ -87,12 +87,12 @@ Select::Select(QObject* parent_)
 
   action = new QAction(tr("Enlarge Selection"), this);
   action->setProperty("menu priority", 790);
-  connect(action, SIGNAL(triggered()), SLOT(enlargeSelection()));
+  connect(action, &QAction::triggered, this, &Select::enlargeSelection);
   m_actions.append(action);
 
   action = new QAction(tr("Shrink Selection"), this);
   action->setProperty("menu priority", 780);
-  connect(action, SIGNAL(triggered()), SLOT(shrinkSelection()));
+  connect(action, &QAction::triggered, this, &Select::shrinkSelection);
   m_actions.append(action);
 
   action = new QAction(this);
@@ -102,7 +102,7 @@ Select::Select(QObject* parent_)
 
   action = new QAction(tr("Create New Layer from Selection"), this);
   action->setProperty("menu priority", 300);
-  connect(action, SIGNAL(triggered()), SLOT(createLayerFromSelection()));
+  connect(action, &QAction::triggered, this, &Select::createLayerFromSelection);
   m_actions.append(action);
 }
 
diff --git a/avogadro/qtplugins/selectiontool/selectiontool.cpp b/avogadro/qtplugins/selectiontool/selectiontool.cpp
index 6e1219d34b..7528b5e0d0 100644
--- a/avogadro/qtplugins/selectiontool/selectiontool.cpp
+++ b/avogadro/qtplugins/selectiontool/selectiontool.cpp
@@ -55,7 +55,8 @@ SelectionTool::SelectionTool(QObject* parent_)
        "\tDrag to select a range of atoms\n"
        "Right Mouse: \tClick outside the molecule to clear selection\n"
        "Use Ctrl to toggle the selection and shift to add to the selection.\n"
-       "Double-Click: \tSelect an entire fragment.").arg(shortcut));
+       "Double-Click: \tSelect an entire fragment.")
+      .arg(shortcut));
   setIcon();
 }
 
@@ -73,10 +74,10 @@ QWidget* SelectionTool::toolWidget() const
 {
   if (m_toolWidget == nullptr) {
     m_toolWidget = new SelectionToolWidget(qobject_cast<QWidget*>(parent()));
-    connect(m_toolWidget, SIGNAL(colorApplied(Vector3ub)), this,
-            SLOT(applyColor(Vector3ub)));
-    connect(m_toolWidget, SIGNAL(changeLayer(int)), this,
-            SLOT(applyLayer(int)));
+    connect(m_toolWidget, &SelectionToolWidget::colorApplied, this,
+            &SelectionTool::applyColor);
+    connect(m_toolWidget, &SelectionToolWidget::changeLayer, this,
+            &SelectionTool::applyLayer);
   }
   return m_toolWidget;
 }
diff --git a/avogadro/qtplugins/selectiontool/selectiontoolwidget.cpp b/avogadro/qtplugins/selectiontool/selectiontoolwidget.cpp
index e1f8b1dce3..55ca1d3bae 100644
--- a/avogadro/qtplugins/selectiontool/selectiontoolwidget.cpp
+++ b/avogadro/qtplugins/selectiontool/selectiontoolwidget.cpp
@@ -15,8 +15,8 @@ SelectionToolWidget::SelectionToolWidget(QWidget* parent)
 {
   m_ui->setupUi(this);
   setDropDown(0, 1);
-  connect(m_ui->applyColorButton, SIGNAL(clicked()), this,
-          SLOT(userClickedColor()));
+  connect(m_ui->applyColorButton, &QAbstractButton::clicked, this,
+          &SelectionToolWidget::userClickedColor);
 }
 
 SelectionToolWidget::~SelectionToolWidget()
diff --git a/avogadro/qtplugins/spacegroup/spacegroup.cpp b/avogadro/qtplugins/spacegroup/spacegroup.cpp
index 4d3190ca20..bcb77f9ade 100644
--- a/avogadro/qtplugins/spacegroup/spacegroup.cpp
+++ b/avogadro/qtplugins/spacegroup/spacegroup.cpp
@@ -48,42 +48,45 @@ SpaceGroup::SpaceGroup(QObject* parent_)
     m_setToleranceAction(new QAction(this))
 {
   m_perceiveSpaceGroupAction->setText(tr("Perceive Space Group…"));
-  connect(m_perceiveSpaceGroupAction, SIGNAL(triggered()),
-          SLOT(perceiveSpaceGroup()));
+  connect(m_perceiveSpaceGroupAction, &QAction::triggered, this,
+          &SpaceGroup::perceiveSpaceGroup);
   m_actions.push_back(m_perceiveSpaceGroupAction);
   m_perceiveSpaceGroupAction->setProperty("menu priority", 90);
 
   m_reduceToPrimitiveAction->setText(tr("Reduce to Primitive"));
-  connect(m_reduceToPrimitiveAction, SIGNAL(triggered()),
-          SLOT(reduceToPrimitive()));
+  connect(m_reduceToPrimitiveAction, &QAction::triggered, this,
+          &SpaceGroup::reduceToPrimitive);
   m_actions.push_back(m_reduceToPrimitiveAction);
   m_reduceToPrimitiveAction->setProperty("menu priority", 80);
 
   m_conventionalizeCellAction->setText(tr("Conventionalize Cell"));
-  connect(m_conventionalizeCellAction, SIGNAL(triggered()),
-          SLOT(conventionalizeCell()));
+  connect(m_conventionalizeCellAction, &QAction::triggered, this,
+          &SpaceGroup::conventionalizeCell);
   m_actions.push_back(m_conventionalizeCellAction);
   m_conventionalizeCellAction->setProperty("menu priority", 70);
 
   m_symmetrizeAction->setText(tr("Symmetrize"));
-  connect(m_symmetrizeAction, SIGNAL(triggered()), SLOT(symmetrize()));
+  connect(m_symmetrizeAction, &QAction::triggered, this,
+          &SpaceGroup::symmetrize);
   m_actions.push_back(m_symmetrizeAction);
   m_symmetrizeAction->setProperty("menu priority", 60);
 
   m_fillUnitCellAction->setText(tr("Fill Unit Cell…"));
-  connect(m_fillUnitCellAction, SIGNAL(triggered()), SLOT(fillUnitCell()));
+  connect(m_fillUnitCellAction, &QAction::triggered, this,
+          &SpaceGroup::fillUnitCell);
   m_actions.push_back(m_fillUnitCellAction);
   // should fall next to the "Wrap Atoms to Unit Cell" action
   m_fillUnitCellAction->setProperty("menu priority", 185);
 
   m_reduceToAsymmetricUnitAction->setText(tr("Reduce to Asymmetric Unit"));
-  connect(m_reduceToAsymmetricUnitAction, SIGNAL(triggered()),
-          SLOT(reduceToAsymmetricUnit()));
+  connect(m_reduceToAsymmetricUnitAction, &QAction::triggered, this,
+          &SpaceGroup::reduceToAsymmetricUnit);
   m_actions.push_back(m_reduceToAsymmetricUnitAction);
   m_reduceToAsymmetricUnitAction->setProperty("menu priority", 40);
 
   m_setToleranceAction->setText(tr("Set Tolerance…"));
-  connect(m_setToleranceAction, SIGNAL(triggered()), SLOT(setTolerance()));
+  connect(m_setToleranceAction, &QAction::triggered, this,
+          &SpaceGroup::setTolerance);
   m_actions.push_back(m_setToleranceAction);
   m_setToleranceAction->setProperty("menu priority", 0);
 
@@ -140,7 +143,8 @@ void SpaceGroup::setMolecule(QtGui::Molecule* mol)
   m_molecule = mol;
 
   if (m_molecule)
-    connect(m_molecule, SIGNAL(changed(uint)), SLOT(moleculeChanged(uint)));
+    connect(m_molecule, &QtGui::Molecule::changed, this,
+            &SpaceGroup::moleculeChanged);
 
   updateActions();
 }
@@ -401,11 +405,11 @@ unsigned short SpaceGroup::selectSpaceGroup()
   view->resizeRowsToContents();
   view->setMinimumWidth(view->horizontalHeader()->length() +
                         view->verticalScrollBar()->sizeHint().width());
-  connect(view, SIGNAL(activated(QModelIndex)), &dialog, SLOT(accept()));
+  connect(view, &QAbstractItemView::activated, &dialog, &QDialog::accept);
   auto* buttons =
     new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel);
-  connect(buttons, SIGNAL(accepted()), &dialog, SLOT(accept()));
-  connect(buttons, SIGNAL(rejected()), &dialog, SLOT(reject()));
+  connect(buttons, &QDialogButtonBox::accepted, &dialog, &QDialog::accept);
+  connect(buttons, &QDialogButtonBox::rejected, &dialog, &QDialog::reject);
   dialog.layout()->addWidget(buttons);
   if (dialog.exec() != QDialog::Accepted)
     return 0;
diff --git a/avogadro/qtplugins/surfaces/orbitals.cpp b/avogadro/qtplugins/surfaces/orbitals.cpp
index 1c446a026d..c52be07465 100644
--- a/avogadro/qtplugins/surfaces/orbitals.cpp
+++ b/avogadro/qtplugins/surfaces/orbitals.cpp
@@ -28,12 +28,12 @@ const double cubePadding = 5.0;
 const int smoothingPasses = 1;
 
 Orbitals::Orbitals(QObject* p)
-  : ExtensionPlugin(p), m_molecule(nullptr), m_dialog(nullptr),
-    m_action(new QAction(this)), m_runningMutex(new QMutex)
+  : ExtensionPlugin(p), m_action(new QAction(this)), m_molecule(nullptr),
+    m_dialog(nullptr), m_runningMutex(new QMutex)
 {
   m_action->setEnabled(false);
   m_action->setText(tr("Molecular Orbitals…"));
-  connect(m_action, SIGNAL(triggered()), SLOT(openDialog()));
+  connect(m_action, &QAction::triggered, this, &Orbitals::openDialog);
 }
 
 Orbitals::~Orbitals()
@@ -88,8 +88,8 @@ void Orbitals::setMolecule(QtGui::Molecule* mol)
       m_dialog->hide();
   }
 
-  connect(m_molecule, SIGNAL(changed(unsigned int)),
-          SLOT(moleculeChanged(unsigned int)));
+  connect(m_molecule, &QtGui::Molecule::changed, this,
+          &Orbitals::moleculeChanged);
 
   // Stuff we manage that will not be valid any longer
   m_queue.clear();
@@ -128,12 +128,12 @@ void Orbitals::loadOrbitals()
 
   if (!m_dialog) {
     m_dialog = new OrbitalWidget(qobject_cast<QWidget*>(parent()), Qt::Window);
-    connect(m_dialog, SIGNAL(orbitalSelected(unsigned int)), this,
-            SLOT(renderOrbital(unsigned int)));
-    connect(m_dialog, SIGNAL(renderRequested(unsigned int, double)), this,
-            SLOT(calculateOrbitalFromWidget(unsigned int, double)));
-    connect(m_dialog, SIGNAL(calculateAll()), this,
-            SLOT(precalculateOrbitals()));
+    connect(m_dialog, &OrbitalWidget::orbitalSelected, this,
+            &Orbitals::renderOrbital);
+    connect(m_dialog, &OrbitalWidget::renderRequested, this,
+            &Orbitals::calculateOrbitalFromWidget);
+    connect(m_dialog, &OrbitalWidget::calculateAll, this,
+            &Orbitals::precalculateOrbitals);
   }
 
   m_dialog->fillTable(m_basis);
@@ -164,12 +164,12 @@ void Orbitals::openDialog()
 {
   if (!m_dialog) {
     m_dialog = new OrbitalWidget(qobject_cast<QWidget*>(parent()), Qt::Window);
-    connect(m_dialog, SIGNAL(orbitalSelected(unsigned int)), this,
-            SLOT(renderOrbital(unsigned int)));
-    connect(m_dialog, SIGNAL(renderRequested(unsigned int, double)), this,
-            SLOT(calculateOrbitalFromWidget(unsigned int, double)));
-    connect(m_dialog, SIGNAL(calculateAll()), this,
-            SLOT(precalculateOrbitals()));
+    connect(m_dialog, &OrbitalWidget::orbitalSelected, this,
+            &Orbitals::renderOrbital);
+    connect(m_dialog, &OrbitalWidget::renderRequested, this,
+            &Orbitals::calculateOrbitalFromWidget);
+    connect(m_dialog, &OrbitalWidget::calculateAll, this,
+            &Orbitals::precalculateOrbitals);
   }
 
   m_dialog->show();
@@ -371,13 +371,14 @@ void Orbitals::calculateCube()
   m_gaussianConcurrent->setMolecule(m_molecule);
 
   auto* watcher = &m_gaussianConcurrent->watcher();
-  connect(watcher, SIGNAL(finished()), this, SLOT(calculateCubeDone()));
+  connect(watcher, &QFutureWatcherBase::finished, this,
+          &Orbitals::calculateCubeDone);
 
   m_dialog->initializeProgress(info->orbital, watcher->progressMinimum(),
                                watcher->progressMaximum(), 1, 3);
 
-  connect(watcher, SIGNAL(progressValueChanged(int)), this,
-          SLOT(updateProgress(int)));
+  connect(watcher, &QFutureWatcherBase::progressValueChanged, this,
+          &Orbitals::updateProgress);
 
 #ifndef NDEBUG
   qDebug() << info->orbital << " Cube calculation started.";
@@ -411,7 +412,8 @@ void Orbitals::calculatePosMesh()
   if (!m_meshGenerator) {
     m_meshGenerator = new QtGui::MeshGenerator;
   }
-  connect(m_meshGenerator, SIGNAL(finished()), SLOT(calculatePosMeshDone()));
+  connect(m_meshGenerator, &QThread::finished, this,
+          &Orbitals::calculatePosMeshDone);
   m_meshGenerator->initialize(cube, posMesh, m_isoValue, smoothingPasses);
   m_meshGenerator->start();
 }
@@ -436,7 +438,8 @@ void Orbitals::calculateNegMesh()
     // shouldn't happen, but better to be careful
     m_meshGenerator = new QtGui::MeshGenerator;
   }
-  connect(m_meshGenerator, SIGNAL(finished()), SLOT(calculateNegMeshDone()));
+  connect(m_meshGenerator, &QThread::finished, this,
+          &Orbitals::calculateNegMeshDone);
   // true indicates that we want to reverse the surface
   m_meshGenerator->initialize(cube, negMesh, -m_isoValue, smoothingPasses,
                               true);
diff --git a/avogadro/qtplugins/surfaces/orbitalwidget.cpp b/avogadro/qtplugins/surfaces/orbitalwidget.cpp
index 754dba28fe..54e86d59ff 100644
--- a/avogadro/qtplugins/surfaces/orbitalwidget.cpp
+++ b/avogadro/qtplugins/surfaces/orbitalwidget.cpp
@@ -39,15 +39,15 @@ OrbitalWidget::OrbitalWidget(QWidget* parent, Qt::WindowFlags f)
   ui.table->hideColumn(OrbitalTableModel::C_Symmetry);
   ui.table->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
 
-  connect(
-    ui.table->selectionModel(),
-    SIGNAL(selectionChanged(const QItemSelection&, const QItemSelection&)),
-    this, SLOT(tableClicked(const QItemSelection&)));
-  connect(ui.push_render, SIGNAL(clicked()), this, SLOT(renderClicked()));
+  connect(ui.table->selectionModel(), &QItemSelectionModel::selectionChanged,
+          this, &OrbitalWidget::tableClicked);
+  connect(ui.push_render, &QAbstractButton::clicked, this,
+          &OrbitalWidget::renderClicked);
 
   // TODO: Implement configure dialog
   ui.push_configure->setVisible(false);
-  connect(ui.push_configure, SIGNAL(clicked()), this, SLOT(configureClicked()));
+  connect(ui.push_configure, &QAbstractButton::clicked, this,
+          &OrbitalWidget::configureClicked);
   readSettings();
 }
 
diff --git a/avogadro/qtplugins/surfaces/surfacedialog.cpp b/avogadro/qtplugins/surfaces/surfacedialog.cpp
index 14228849de..f2904dc99e 100644
--- a/avogadro/qtplugins/surfaces/surfacedialog.cpp
+++ b/avogadro/qtplugins/surfaces/surfacedialog.cpp
@@ -37,8 +37,10 @@ SurfaceDialog::SurfaceDialog(QWidget* parent_, Qt::WindowFlags f)
   connect(m_ui->smoothingCombo, SIGNAL(currentIndexChanged(int)),
           SLOT(smoothingComboChanged(int)));
   connect(m_ui->stepValue, SIGNAL(valueChanged(int)), SIGNAL(stepChanged(int)));
-  connect(m_ui->calculateButton, SIGNAL(clicked()), SLOT(calculateClicked()));
-  connect(m_ui->recordButton, SIGNAL(clicked()), SLOT(record()));
+  connect(m_ui->calculateButton, &QAbstractButton::clicked, this,
+          &SurfaceDialog::calculateClicked);
+  connect(m_ui->recordButton, &QAbstractButton::clicked, this,
+          &SurfaceDialog::record);
 }
 
 SurfaceDialog::~SurfaceDialog()
diff --git a/avogadro/qtplugins/surfaces/surfaces.cpp b/avogadro/qtplugins/surfaces/surfaces.cpp
index 716c583f0a..5e299a3037 100644
--- a/avogadro/qtplugins/surfaces/surfaces.cpp
+++ b/avogadro/qtplugins/surfaces/surfaces.cpp
@@ -82,9 +82,11 @@ Surfaces::Surfaces(QObject* p) : ExtensionPlugin(p), d(new PIMPL())
 {
   auto action = new QAction(this);
   action->setText(tr("Create Surfaces…"));
-  connect(action, SIGNAL(triggered()), SLOT(surfacesActivated()));
-  connect(&m_displayMeshWatcher, SIGNAL(finished()), SLOT(displayMesh()));
-  connect(&m_performEDTStepWatcher, SIGNAL(finished()), SLOT(performEDTStep()));
+  connect(action, &QAction::triggered, this, &Surfaces::surfacesActivated);
+  connect(&m_displayMeshWatcher, &QFutureWatcherBase::finished, this,
+          &Surfaces::displayMesh);
+  connect(&m_performEDTStepWatcher, &QFutureWatcherBase::finished, this,
+          &Surfaces::performEDTStep);
 
   m_actions.push_back(action);
 
@@ -240,7 +242,8 @@ void Surfaces::setMolecule(QtGui::Molecule* mol)
   m_molecule = mol;
 
   if (m_molecule != nullptr) {
-    connect(m_molecule, SIGNAL(changed(uint)), SLOT(moleculeChanged(uint)));
+    connect(m_molecule, &QtGui::Molecule::changed, this,
+            &Surfaces::moleculeChanged);
   }
 }
 
@@ -268,10 +271,12 @@ void Surfaces::surfacesActivated()
 {
   if (!m_dialog) {
     m_dialog = new SurfaceDialog(qobject_cast<QWidget*>(parent()));
-    connect(m_dialog, SIGNAL(calculateClickedSignal()),
-            SLOT(calculateSurface()));
-    connect(m_dialog, SIGNAL(recordClicked()), SLOT(recordMovie()));
-    connect(m_dialog, SIGNAL(stepChanged(int)), SLOT(stepChanged(int)));
+    connect(m_dialog, &SurfaceDialog::calculateClickedSignal, this,
+            &Surfaces::calculateSurface);
+    connect(m_dialog, &SurfaceDialog::recordClicked, this,
+            &Surfaces::recordMovie);
+    connect(m_dialog, &SurfaceDialog::stepChanged, this,
+            &Surfaces::stepChanged);
   }
 
   if (m_basis) {
@@ -622,14 +627,15 @@ void Surfaces::calculateQM(Type type, int index, bool beta, float isoValue,
 
     if (connectSlots) {
       connect(&m_gaussianConcurrent->watcher(),
-              SIGNAL(progressValueChanged(int)), m_progressDialog,
-              SLOT(setValue(int)));
+              &QFutureWatcherBase::progressValueChanged, m_progressDialog,
+              &QProgressDialog::setValue);
       connect(&m_gaussianConcurrent->watcher(),
-              SIGNAL(progressRangeChanged(int, int)), m_progressDialog,
-              SLOT(setRange(int, int)));
-      connect(m_gaussianConcurrent, SIGNAL(finished()), SLOT(displayMesh()));
-      connect(m_progressDialog, SIGNAL(canceled()),
-              &m_gaussianConcurrent->watcher(), SLOT(cancel()));
+              &QFutureWatcherBase::progressRangeChanged, m_progressDialog,
+              &QProgressDialog::setRange);
+      connect(m_gaussianConcurrent, &QtGui::GaussianSetConcurrent::finished,
+              this, &Surfaces::displayMesh);
+      connect(m_progressDialog, &QProgressDialog::canceled,
+              &m_gaussianConcurrent->watcher(), &QFutureWatcherBase::cancel);
     }
   } else {
     // slaters
@@ -639,14 +645,16 @@ void Surfaces::calculateQM(Type type, int index, bool beta, float isoValue,
     m_progressDialog->setValue(m_slaterConcurrent->watcher().progressValue());
     m_progressDialog->show();
 
-    connect(&m_slaterConcurrent->watcher(), SIGNAL(progressValueChanged(int)),
-            m_progressDialog, SLOT(setValue(int)));
     connect(&m_slaterConcurrent->watcher(),
-            SIGNAL(progressRangeChanged(int, int)), m_progressDialog,
-            SLOT(setRange(int, int)));
-    connect(m_progressDialog, SIGNAL(canceled()),
-            &m_slaterConcurrent->watcher(), SLOT(cancel()));
-    connect(m_slaterConcurrent, SIGNAL(finished()), SLOT(displayMesh()));
+            &QFutureWatcherBase::progressValueChanged, m_progressDialog,
+            &QProgressDialog::setValue);
+    connect(&m_slaterConcurrent->watcher(),
+            &QFutureWatcherBase::progressRangeChanged, m_progressDialog,
+            &QProgressDialog::setRange);
+    connect(m_progressDialog, &QProgressDialog::canceled,
+            &m_slaterConcurrent->watcher(), &QFutureWatcherBase::cancel);
+    connect(m_slaterConcurrent, &QtGui::SlaterSetConcurrent::finished, this,
+            &Surfaces::displayMesh);
   }
 }
 
@@ -704,7 +712,8 @@ void Surfaces::displayMesh()
     m_mesh1 = m_molecule->addMesh();
   if (!m_meshGenerator1) {
     m_meshGenerator1 = new QtGui::MeshGenerator;
-    connect(m_meshGenerator1, SIGNAL(finished()), SLOT(meshFinished()));
+    connect(m_meshGenerator1, &QThread::finished, this,
+            &Surfaces::meshFinished);
   }
   m_meshGenerator1->initialize(m_cube, m_mesh1, m_isoValue, m_smoothingPasses);
 
@@ -720,7 +729,8 @@ void Surfaces::displayMesh()
       m_mesh2 = m_molecule->addMesh();
     if (!m_meshGenerator2) {
       m_meshGenerator2 = new QtGui::MeshGenerator;
-      connect(m_meshGenerator2, SIGNAL(finished()), SLOT(meshFinished()));
+      connect(m_meshGenerator2, &QThread::finished, this,
+              &Surfaces::meshFinished);
     }
     m_meshGenerator2->initialize(m_cube, m_mesh2, -m_isoValue,
                                  m_smoothingPasses, true);
diff --git a/avogadro/qtplugins/svg/svg.cpp b/avogadro/qtplugins/svg/svg.cpp
index ee6e9ba359..271d398c9b 100644
--- a/avogadro/qtplugins/svg/svg.cpp
+++ b/avogadro/qtplugins/svg/svg.cpp
@@ -5,11 +5,11 @@
 
 #include "svg.h"
 
+#include <QAction>
 #include <QDir>
 #include <QFile>
 #include <QFileDialog>
 #include <QSvgGenerator>
-#include <QAction>
 #include <avogadro/qtopengl/glwidget.h>
 #include <avogadro/rendering/camera.h>
 #include <avogadro/rendering/scene.h>
@@ -27,9 +27,10 @@ const Vector3ub SVG::DEFAULT_BOND_COLOR = Vector3ub(125, 125, 125);
 
 SVG::SVG(QObject* parent_)
   : Avogadro::QtGui::ExtensionPlugin(parent_), m_molecule(nullptr),
-    m_scene(nullptr), m_camera(nullptr), m_action(new QAction(tr("&SVG…"), this))
+    m_scene(nullptr), m_camera(nullptr),
+    m_action(new QAction(tr("&SVG…"), this))
 {
-  connect(m_action, SIGNAL(triggered()), SLOT(render()));
+  connect(m_action, &QAction::triggered, this, &SVG::render);
 }
 
 SVG::~SVG() {}
@@ -277,4 +278,4 @@ void SVG::render()
   painter.end();
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/symmetry/symmetry.cpp b/avogadro/qtplugins/symmetry/symmetry.cpp
index 44985f4d85..7b2cd20309 100644
--- a/avogadro/qtplugins/symmetry/symmetry.cpp
+++ b/avogadro/qtplugins/symmetry/symmetry.cpp
@@ -9,8 +9,8 @@
 
 #include "symmetryutil.h"
 
-//#include <avogadro/core/unitcell.h>
-//#include <avogadro/core/crystaltools.h>
+// #include <avogadro/core/unitcell.h>
+// #include <avogadro/core/crystaltools.h>
 
 #include <avogadro/qtgui/molecule.h>
 
@@ -30,17 +30,16 @@ using namespace Avogadro::QtPlugins::SymmetryUtil;
 namespace Avogadro::QtPlugins {
 
 Symmetry::Symmetry(QObject* parent_)
-  : Avogadro::QtGui::ExtensionPlugin(parent_)
-  , m_molecule(nullptr)
-  , m_symmetryWidget(nullptr)
-  , m_viewSymmetryAction(new QAction(this))
+  : Avogadro::QtGui::ExtensionPlugin(parent_), m_molecule(nullptr),
+    m_symmetryWidget(nullptr), m_viewSymmetryAction(new QAction(this))
 {
 
   m_ctx = msymCreateContext();
 
   m_viewSymmetryAction->setText(tr("Symmetry…"));
   m_viewSymmetryAction->setProperty("menu priority", -50);
-  connect(m_viewSymmetryAction, SIGNAL(triggered()), SLOT(viewSymmetry()));
+  connect(m_viewSymmetryAction, &QAction::triggered, this,
+          &Symmetry::viewSymmetry);
   m_actions.push_back(m_viewSymmetryAction);
 
   /*
@@ -95,7 +94,8 @@ void Symmetry::setMolecule(QtGui::Molecule* mol)
     m_symmetryWidget->setMolecule(m_molecule);
 
   if (m_molecule)
-    connect(m_molecule, SIGNAL(changed(uint)), SLOT(moleculeChanged(uint)));
+    connect(m_molecule, &QtGui::Molecule::changed, this,
+            &Symmetry::moleculeChanged);
 
   updateActions();
   m_dirty = true;
@@ -154,10 +154,10 @@ void Symmetry::viewSymmetry()
   if (!m_symmetryWidget) {
     m_symmetryWidget = new SymmetryWidget(qobject_cast<QWidget*>(parent()));
     m_symmetryWidget->setMolecule(m_molecule);
-    connect(m_symmetryWidget, SIGNAL(detectSymmetry()), SLOT(detectSymmetry()));
-    connect(m_symmetryWidget,
-            SIGNAL(symmetrizeMolecule()),
-            SLOT(symmetrizeMolecule()));
+    connect(m_symmetryWidget, &SymmetryWidget::detectSymmetry, this,
+            &Symmetry::detectSymmetry);
+    connect(m_symmetryWidget, &SymmetryWidget::symmetrizeMolecule, this,
+            &Symmetry::symmetrizeMolecule);
   }
 
   if (m_dirty) {
@@ -376,4 +376,4 @@ void Symmetry::standardOrientation()
                           | Molecule::Atoms | Molecule::UnitCell);
 }*/
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/qtplugins/symmetry/symmetrywidget.cpp b/avogadro/qtplugins/symmetry/symmetrywidget.cpp
index 5c368cc630..be26eecbe4 100644
--- a/avogadro/qtplugins/symmetry/symmetrywidget.cpp
+++ b/avogadro/qtplugins/symmetry/symmetrywidget.cpp
@@ -63,11 +63,12 @@ msym_thresholds_t sloppy_thresholds = {
 };
 
 SymmetryWidget::SymmetryWidget(QWidget* parent_)
-  : QWidget(parent_), m_ui(new Ui::SymmetryWidget), m_molecule(nullptr),
+  : QWidget(parent_), m_ui(new Ui::SymmetryWidget),
     m_equivalenceTreeModel(new QStandardItemModel(this)),
     m_operationsTableModel(new OperationsTableModel(this)),
-    m_subgroupsTreeModel(new QStandardItemModel(this)), m_es(nullptr),
-    m_sops(nullptr), m_sg(nullptr), m_sopsl(0), m_sgl(0), m_radius(0.0)
+    m_subgroupsTreeModel(new QStandardItemModel(this)), m_molecule(nullptr),
+    m_es(nullptr), m_sops(nullptr), m_sg(nullptr), m_sopsl(0), m_sgl(0),
+    m_radius(0.0)
 {
   setWindowFlags(Qt::Dialog);
   m_ui->setupUi(this);
@@ -81,10 +82,10 @@ SymmetryWidget::SymmetryWidget(QWidget* parent_)
   m_ui->subgroupsTree->setModel(m_subgroupsTreeModel);
   m_ui->subgroupsTree->setItemDelegateForColumn(0, new RichTextDelegate(this));
 
-  connect(m_ui->detectSymmetryButton, SIGNAL(clicked()),
-          SIGNAL(detectSymmetry()));
-  connect(m_ui->symmetrizeMoleculeButton, SIGNAL(clicked()),
-          SIGNAL(symmetrizeMolecule()));
+  connect(m_ui->detectSymmetryButton, &QAbstractButton::clicked, this,
+          &SymmetryWidget::detectSymmetry);
+  connect(m_ui->symmetrizeMoleculeButton, &QAbstractButton::clicked, this,
+          &SymmetryWidget::symmetrizeMolecule);
 
   connect(
     m_ui->equivalenceTree->selectionModel(),
@@ -97,11 +98,9 @@ SymmetryWidget::SymmetryWidget(QWidget* parent_)
     SIGNAL(selectionChanged(const QItemSelection&, const QItemSelection&)),
     SLOT(operationsSelectionChanged(const QItemSelection&,
                                     const QItemSelection&)));
-  connect(
-    m_ui->subgroupsTree->selectionModel(),
-    SIGNAL(selectionChanged(const QItemSelection&, const QItemSelection&)),
-    SLOT(
-      subgroupsSelectionChanged(const QItemSelection&, const QItemSelection&)));
+  connect(m_ui->subgroupsTree->selectionModel(),
+          &QItemSelectionModel::selectionChanged, this,
+          &SymmetryWidget::subgroupsSelectionChanged);
 }
 
 SymmetryWidget::~SymmetryWidget()
@@ -118,7 +117,8 @@ void SymmetryWidget::setMolecule(QtGui::Molecule* molecule)
     m_molecule = molecule;
 
     if (m_molecule) {
-      connect(m_molecule, SIGNAL(changed(uint)), SLOT(moleculeChanged(uint)));
+      connect(m_molecule, &QtGui::Molecule::changed, this,
+              &SymmetryWidget::moleculeChanged);
     }
   }
 }
diff --git a/avogadro/qtplugins/templatetool/templatetool.cpp b/avogadro/qtplugins/templatetool/templatetool.cpp
index a631d33441..a9c672be57 100644
--- a/avogadro/qtplugins/templatetool/templatetool.cpp
+++ b/avogadro/qtplugins/templatetool/templatetool.cpp
@@ -196,7 +196,7 @@ QUndoCommand* TemplateTool::keyPressEvent(QKeyEvent* e)
 
   // Set a timer to clear the buffer on first keypress:
   if (m_keyPressBuffer.isEmpty())
-    QTimer::singleShot(2000, this, SLOT(clearKeyPressBuffer()));
+    QTimer::singleShot(2000, this, &TemplateTool::clearKeyPressBuffer);
 
   m_keyPressBuffer.append(m_keyPressBuffer.isEmpty() ? e->text().toUpper()
                                                      : e->text().toLower());
diff --git a/avogadro/qtplugins/templatetool/templatetoolwidget.cpp b/avogadro/qtplugins/templatetool/templatetoolwidget.cpp
index a87cdd8418..3c07b88687 100644
--- a/avogadro/qtplugins/templatetool/templatetoolwidget.cpp
+++ b/avogadro/qtplugins/templatetool/templatetoolwidget.cpp
@@ -47,7 +47,7 @@ enum LigandType
 
 TemplateToolWidget::TemplateToolWidget(QWidget* parent_)
   : QWidget(parent_), m_ui(new Ui::TemplateToolWidget),
-    m_elementSelector(nullptr), m_fragmentDialog(nullptr), m_currentElement(26)
+    m_fragmentDialog(nullptr), m_elementSelector(nullptr), m_currentElement(26)
 {
   m_ui->setupUi(this);
 
@@ -217,8 +217,8 @@ void TemplateToolWidget::groupChanged(int index)
       m_fragmentDialog->deleteLater();
 
     m_fragmentDialog = new QtGui::InsertFragmentDialog(this, path);
-    connect(m_fragmentDialog, SIGNAL(performInsert(const QString&, bool)), this,
-            SLOT(otherLigandInsert(const QString&, bool)));
+    connect(m_fragmentDialog, &QtGui::InsertFragmentDialog::performInsert, this,
+            &TemplateToolWidget::otherLigandInsert);
     m_fragmentDialog->show();
     return;
   }
@@ -268,8 +268,8 @@ void TemplateToolWidget::ligandChanged(int index)
       m_fragmentDialog->deleteLater();
 
     m_fragmentDialog = new QtGui::InsertFragmentDialog(this, path);
-    connect(m_fragmentDialog, SIGNAL(performInsert(const QString&, bool)), this,
-            SLOT(otherLigandInsert(const QString&, bool)));
+    connect(m_fragmentDialog, &QtGui::InsertFragmentDialog::performInsert, this,
+            &TemplateToolWidget::otherLigandInsert);
     m_fragmentDialog->show();
     return;
   }
@@ -388,8 +388,8 @@ void TemplateToolWidget::elementChanged(int index)
     if (itemData.toInt() == ELEMENT_SELECTOR_TAG) {
       if (!m_elementSelector) {
         m_elementSelector = new QtGui::PeriodicTableView(this);
-        connect(m_elementSelector, SIGNAL(elementChanged(int)), this,
-                SLOT(elementSelectedFromTable(int)));
+        connect(m_elementSelector, &QtGui::PeriodicTableView::elementChanged,
+                this, &TemplateToolWidget::elementSelectedFromTable);
       }
       m_elementSelector->setElement(m_currentElement);
       m_elementSelector->show();
diff --git a/avogadro/qtplugins/vibrations/vibrationdialog.cpp b/avogadro/qtplugins/vibrations/vibrationdialog.cpp
index 07b7175cae..c613d13e93 100644
--- a/avogadro/qtplugins/vibrations/vibrationdialog.cpp
+++ b/avogadro/qtplugins/vibrations/vibrationdialog.cpp
@@ -23,10 +23,12 @@ VibrationDialog::VibrationDialog(QWidget* parent_, Qt::WindowFlags f)
   m_ui->tableView->setSelectionBehavior(QAbstractItemView::SelectRows);
   m_ui->tableView->setSelectionMode(QAbstractItemView::ExtendedSelection);
 
-  connect(m_ui->amplitudeSlider, SIGNAL(sliderMoved(int)),
-          SIGNAL(amplitudeChanged(int)));
-  connect(m_ui->startButton, SIGNAL(clicked(bool)), SIGNAL(startAnimation()));
-  connect(m_ui->stopButton, SIGNAL(clicked(bool)), SIGNAL(stopAnimation()));
+  connect(m_ui->amplitudeSlider, &QAbstractSlider::sliderMoved, this,
+          &VibrationDialog::amplitudeChanged);
+  connect(m_ui->startButton, &QAbstractButton::clicked, this,
+          &VibrationDialog::startAnimation);
+  connect(m_ui->stopButton, &QAbstractButton::clicked, this,
+          &VibrationDialog::stopAnimation);
 }
 
 VibrationDialog::~VibrationDialog()
@@ -38,16 +40,16 @@ void VibrationDialog::setMolecule(QtGui::Molecule* molecule)
 {
   if (m_ui->tableView->selectionModel()) {
     disconnect(m_ui->tableView->selectionModel(),
-               SIGNAL(currentRowChanged(QModelIndex, QModelIndex)), this,
-               SLOT(selectRow(QModelIndex)));
+               &QItemSelectionModel::currentRowChanged, this,
+               &VibrationDialog::selectRow);
   }
 
   auto* model = new VibrationModel(this);
   model->setMolecule(molecule);
   m_ui->tableView->setModel(model);
   connect(m_ui->tableView->selectionModel(),
-          SIGNAL(currentRowChanged(QModelIndex, QModelIndex)),
-          SLOT(selectRow(QModelIndex)));
+          &QItemSelectionModel::currentRowChanged, this,
+          &VibrationDialog::selectRow);
 
   Core::Array<double> freqs = molecule->vibrationFrequencies();
   for (size_t i = 0; i < freqs.size(); ++i) {
diff --git a/avogadro/qtplugins/vibrations/vibrations.cpp b/avogadro/qtplugins/vibrations/vibrations.cpp
index 5f351e2244..45003c8b05 100644
--- a/avogadro/qtplugins/vibrations/vibrations.cpp
+++ b/avogadro/qtplugins/vibrations/vibrations.cpp
@@ -25,7 +25,7 @@ Vibrations::Vibrations(QObject* p)
   auto* action = new QAction(this);
   action->setEnabled(false);
   action->setText(tr("Vibrational Modes…"));
-  connect(action, SIGNAL(triggered()), SLOT(openDialog()));
+  connect(action, &QAction::triggered, this, &Vibrations::openDialog);
   m_actions.push_back(action);
 }
 
@@ -63,8 +63,8 @@ void Vibrations::setMolecule(QtGui::Molecule* mol)
   if (isVibrational)
     openDialog();
 
-  connect(m_molecule, SIGNAL(changed(unsigned int)),
-          SLOT(moleculeChanged(unsigned int)));
+  connect(m_molecule, &QtGui::Molecule::changed, this,
+          &Vibrations::moleculeChanged);
 }
 
 void Vibrations::moleculeChanged(unsigned int changes)
@@ -207,7 +207,7 @@ void Vibrations::startVibrationAnimation()
 
   if (!m_timer) {
     m_timer = new QTimer(this);
-    connect(m_timer, SIGNAL(timeout()), SLOT(advanceFrame()));
+    connect(m_timer, &QTimer::timeout, this, &Vibrations::advanceFrame);
   }
   if (!m_timer->isActive()) {
     m_timer->start(50);
@@ -228,11 +228,14 @@ void Vibrations::openDialog()
 {
   if (!m_dialog) {
     m_dialog = new VibrationDialog(qobject_cast<QWidget*>(parent()));
-    connect(m_dialog, SIGNAL(modeChanged(int)), SLOT(setMode(int)));
-    connect(m_dialog, SIGNAL(amplitudeChanged(int)), SLOT(setAmplitude(int)));
-    connect(m_dialog, SIGNAL(startAnimation()),
-            SLOT(startVibrationAnimation()));
-    connect(m_dialog, SIGNAL(stopAnimation()), SLOT(stopVibrationAnimation()));
+    connect(m_dialog, &VibrationDialog::modeChanged, this,
+            &Vibrations::setMode);
+    connect(m_dialog, &VibrationDialog::amplitudeChanged, this,
+            &Vibrations::setAmplitude);
+    connect(m_dialog, &VibrationDialog::startAnimation, this,
+            &Vibrations::startVibrationAnimation);
+    connect(m_dialog, &VibrationDialog::stopAnimation, this,
+            &Vibrations::stopVibrationAnimation);
   }
   if (m_molecule)
     m_dialog->setMolecule(m_molecule);
diff --git a/avogadro/qtplugins/vrml/vrml.cpp b/avogadro/qtplugins/vrml/vrml.cpp
index 8d52d60f4c..8f33b05c89 100644
--- a/avogadro/qtplugins/vrml/vrml.cpp
+++ b/avogadro/qtplugins/vrml/vrml.cpp
@@ -10,11 +10,11 @@
 #include <avogadro/rendering/scene.h>
 #include <avogadro/rendering/vrmlvisitor.h>
 
+#include <QAction>
 #include <QtCore/QTextStream>
 #include <QtGui/QClipboard>
 #include <QtGui/QIcon>
 #include <QtGui/QKeySequence>
-#include <QAction>
 #include <QtWidgets/QApplication>
 #include <QtWidgets/QFileDialog>
 #include <QtWidgets/QMessageBox>
@@ -28,12 +28,10 @@ VRML::VRML(QObject* p)
   : Avogadro::QtGui::ExtensionPlugin(p), m_molecule(nullptr), m_scene(nullptr),
     m_camera(nullptr), m_action(new QAction(tr("VRML Render…"), this))
 {
-  connect(m_action, SIGNAL(triggered()), SLOT(render()));
+  connect(m_action, &QAction::triggered, this, &VRML::render);
 }
 
-VRML::~VRML()
-{
-}
+VRML::~VRML() {}
 
 QList<QAction*> VRML::actions() const
 {
@@ -82,4 +80,4 @@ void VRML::render()
   file.close();
 }
 
-} // namespace Avogadro
+} // namespace Avogadro::QtPlugins
diff --git a/avogadro/quantumio/orca.cpp b/avogadro/quantumio/orca.cpp
index 72c346f139..5a26526295 100644
--- a/avogadro/quantumio/orca.cpp
+++ b/avogadro/quantumio/orca.cpp
@@ -484,6 +484,7 @@ void ORCAOutput::processLine(std::istream& in, GaussianSet* basis)
         }
 
         m_currentMode = NotParsing;
+        break;
       }
       case OrbitalEnergies: {
         if (key.empty())
@@ -681,6 +682,7 @@ void ORCAOutput::processLine(std::istream& in, GaussianSet* basis)
             break; // hit the blank line
         }
         m_currentMode = NotParsing;
+        break;
       }
       case ECD: {
         if (key.empty())
@@ -709,6 +711,7 @@ void ORCAOutput::processLine(std::istream& in, GaussianSet* basis)
             break; // hit the blank line
         }
         m_currentMode = NotParsing;
+        break;
       }
       case NMR: {
         if (key.empty())
diff --git a/avogadro/rendering/arrowgeometry.cpp b/avogadro/rendering/arrowgeometry.cpp
index b1aac510fb..370f0b8d4f 100644
--- a/avogadro/rendering/arrowgeometry.cpp
+++ b/avogadro/rendering/arrowgeometry.cpp
@@ -42,7 +42,7 @@ class ArrowGeometry::Private
 };
 
 ArrowGeometry::ArrowGeometry()
-  : m_dirty(false), d(new Private), m_color(0, 255, 0)
+  : m_color(0, 255, 0), m_dirty(false), d(new Private)
 {
 }
 
diff --git a/avogadro/rendering/solidpipeline.cpp b/avogadro/rendering/solidpipeline.cpp
index 4707c85ec8..ab5d96596d 100644
--- a/avogadro/rendering/solidpipeline.cpp
+++ b/avogadro/rendering/solidpipeline.cpp
@@ -84,11 +84,11 @@ void initializeFramebuffer(GLuint* outFBO, GLuint* texRGB, GLuint* texDepth)
 }
 
 SolidPipeline::SolidPipeline()
-  : m_pixelRatio(1.0f), m_aoEnabled(false), m_dofEnabled(false),
-    m_aoStrength(1.0f), m_fogStrength(1.0f), m_fogPosition(1.0),
-    m_fogEnabled(true), m_edEnabled(false), m_edStrength(1.0f), m_width(0),
-    m_height(0), m_dofStrength(1.0f), m_dofPosition(1.0),
-    m_backgroundColor(0, 0, 0, 0), d(new Private)
+  : m_pixelRatio(1.0f), m_aoEnabled(false), m_dofStrength(1.0f),
+    m_dofPosition(1.0), m_dofEnabled(false), m_fogPosition(1.0),
+    m_backgroundColor(0, 0, 0, 0), m_fogEnabled(true), m_aoStrength(1.0f),
+    m_fogStrength(1.0f), m_edEnabled(false), m_edStrength(1.0f), m_width(0),
+    m_height(0), d(new Private)
 {
 }