FEATURES

* Hartree-Fock (up to ~5000 basis)

  - Non-relativistic restricted open-shell, unrestricted HF
  - Scalar relativistic HF
  - 2-component relativistic HF
  - 4-component relativistic Dirac-Hartree-Fock
  - Density fitting HF
  - Second order SCF
  - General J/K build function
  - DIIS, EDIIS, ADIIS and second order solver
  - SCF wavefunction (RHF, UHF, GHF) stability analysis
  - Generalized Hartree-Fock (GHF)


* DFT (up to ~5000 basis)

  - Non-relativistic restricted, restricted open-shell, unrestricted Kohn-Sham
  - Scalar relativistic DFT
  - Density fitting DFT
  - General XC functional evaluator (for Libxc or XcFun)
  - General AO evaluator
  - VV10 NLC functional for finite size systems
  - range-separated hybrid features for RKS and UKS, including
    > Analytical nuclear gradients
    > Second order SCF
    > Hessian and frequency
    > TDDFT
    > TDDFT nuclear gradients
    > NMR


* TDSCF/TDDFT

  - TDA (and density-fitting TDA) for RHF, UHF, RKS and UKS methods
  - TDHF (and density-fitting TDHF) for RHF and UHF methods
  - TDDFT (and density-fitting TDDFT) for RKS and UKS methods
  - TDA nuclear gradients for RHF, UHF, RKS and UKS methods
  - TDHF nuclear gradients for RHF and UHF methods
  - TDDFT nuclear gradients for RKS and UKS methods
  - Natural transition orbital analysis
  - direct-RPA (no exchange, aka TDH)
  - direct-TDA (TDA without exchange)


* GW methods
  - G0W0 approximation


* General CASCI/CASSCF solver (up to ~3000 basis)

  - State-average CASCI/CASSCF
  - State-specific CASCI/CASSCF for excited states
  - Multiple roots CASCI
  - Support DMRG as plugin FCI solver to do DMRG-CASSCF
  - Support FCIQMC as plugin FCI solver to do FCIQMC-CASSCF
  - Support Selected CI algorithm as plugin FCI solver to do SHCI-CASSCF
  - UCASSCF
  - Density-fitting CASSCF
  - DMET-CAS and AVAS active space constructor
  - CASCI and CASSCF analytical nuclear gradients


* MP2 (up to ~200 occupied, ~2000 virtual orbitals)

  - Canonical RMP2, UMP2, GMP2
  - Density-fitting RMP2
  - RMP2, UMP2 and GMP2 1-particle and 2-particle density matrices
  - RMP2 and UMP2 nuclear gradients


* CCSD (up to ~100 occupied, ~1500 virtual orbitals)

  - canonical RCCSD, UCCSD
  - canonical RCCSD, UCCSD lambda solver
  - RCCSD, UCCSD and GCCSD 1-particle and 2-particle density matrices
  - RCCSD and UCCSD nuclear gradients
  - EOM-IP/EA/EE-RCCSD and EOM-IP/EA/EE-UCCSD
  - RCC2
  - Density-fitting RCCSD


* CCSD(T)

  - RCCSD(T) and UCCSD(T)
  - RCCSD(T), UCCSD(T) and GCCSD(T) 1- and 2-particle density matrices
  - RCCSD(T) and UCCSD(T) analytical nuclear gradients


* CI

  - RCISD, UCISD and GCISD
  - RCISD, UCISD and GCISD 1, 2-particle density matrices
  - Selected-CI
  - Selected-CI 1, 2-particle density matrices
  - RCISD, UCISD and GCISD 1-particle transition density matrices


* Full CI

  - Direct-CI solver for spin degenerated Hamiltonian (RHF-FCI)
  - Direct-CI solver for spin non-degenerated Hamiltonian (UHF-FCI)
  - 1, and 2-particle transition density matrices
  - 1, 2, 3, and 4-particle density matrices
  - CI wavefunction overlap


* Analytical Nuclear Gradients

  - Non-relativistic HF nuclear gradients
  - 4-component DHF nuclear gradients
  - Non-relativistic DFT nuclear gradients
  - Non-relativistic CISD nuclear gradients
  - Non-relativistic CCSD and CCSD(T) nuclear gradients
  - Non-relativistic CASCI and CASSCF nuclear gradients
  - Non-relativistic TDA, TDHF and TDDFT nuclear gradients
  - Non-relativistic nuclear gradients with SF-X2C-1e correction
  - ECP nuclear gradients
  - nuclear gradients for solvent model ddCOSMO
  - Frozen orbitals for MP2, CISD, CCSD, CCSD(T), CASCI, CASSCF nuclear gradients


* Nuclear Hessian

  - Non-relativistic HF nuclear hessian
  - Non-relativistic DFT nuclear hessian
  - Non-relativistic nuclear hessian with SF-X2C-1e correction
  - ECP nuclear hessian


* Properties

  - Non-relativistic RHF, UHF, RKS, UKS NMR shielding
  - 4-component DHF NMR shielding
  - Non-relativistic RHF, UHF spin-spin coupling
  - 4-component DHF spin-spin coupling
  - Non-relativistic UHF, UKS hyperfine coupling
  - 4-component DHF hyperfine coupling
  - Non-relativistic UHF, UKS g-tensor
  - 4-component DHF g-tensor
  - Non-relativistic UHF zero-field splitting
  - Molecular electrostatic potential (MEP)

* MRPT

  - Strongly contracted NEVPT2 (SC-NEVPT2)
  - DMRG-NEVPT2
  - IC-MPS-PT2


* Extended systems with periodic boundary condition

  - gamma point RHF, ROHF, UHF, RKS, ROKS, UKS
  - gamma point TDDFT, MP2, CCSD
  - RHF, ROHF, UHF, GHF, RKS, ROKS, UKS with k-point sampling
  - Restricted MP2 with k-point sampling
  - KRCCSD (RCCSD with k-point sampling)
  - KUCCSD
  - KGCCSD (Generalized CCSD with k-point sampling)
  - k-point GCCSD(T) and RCCSD(T)
  - k-point EOM-IP/EA-CCSD
  - PBC AO integrals
  - PBC MO integral transformation
  - PBC density fitting and mixed-density fitting methods
  - Smearing for mean-field methods
  - Low-dimensional (0D, 1D, 2D) PBC systems
  - (restricted and unrestricted) TDA, TDHF and TDDFT with k-point sampling
  - Multigrid DFT


* Relativistic effects

  - 4-component HF with Dirac-Coulomb Hamiltonian (DHF)
  - 4-component DHF with Gaunt and Breit corrections
  - 2-component X2C HF
  - 4-component and 2-component Kohn-Sham DFT (LDA only)


* AO integrals

  - Interface to access all AO integrals of Libcint library
  - 1-electron real-GTO and spinor-GTO integrals
  - 2-electron real-GTO and spinor-GTO integrals
  - 3-center 1-electron real-GTO and spinor-GTO integrals
  - 3-center 2-electron real-GTO and spinor-GTO integrals
  - General basis value evaluator (for numeric integration)
  - PBC 1-electron integrals
  - PBC 2-electron integrals
  - F12 integrals


* MO integrals

  - 2-electron integral transformation for any integrals provided by
    Libcint library
  - Support for 4-index integral transformation with 4 different orbitals
  - PBC 2-electron MO integrals
  - Integral transformation for (4-component and 2-compoent relativistic) spinor
    integrals


* Localizer

  - Boys
  - Edmiston
  - Meta-Lowdin for both finite size and PBC systems
  - Natural atomic orbital (NAO) for both finite size and PBC systems
  - Intrinsic atomic orbital (IAO) for both finite size and PBC systems
  - Pipek-Mezey for both finite size and PBC systems
  - Intrinsic bond orbital (IBO) for both finite size and PBC systems


* Geometry optimization

  - HF, DFT, CCSD, CCSD(T), CISD, CASCI, CASSCF and TDSCF/TDDFT with pyberny
    geometry optimizer


* D2h symmetry and linear molecule symmetry

  - Molecule symmetry detection
  - Symmetry adapted basis
  - Label orbital symmetry on the fly
  - Hot update symmetry information
  - Function to symmetrize given orbital space


* Solvent model
  - ddCOSMO
  - ddPCM
  - ddCOSMO analytical nuclear gradients


* Tools

  - fcidump writer
  - molden writer and reader
  - cubegen writer
  - Molpro XML reader
  - (GAMESS-format) wfn writer
  - Vasp CHGCAR-format writer