New features:
* Spinor-GTO evaluator
* Dirac-Kohn-Sham (LDA functional)
* EDIIS and ADIIS
* Periodic CCSD with k-point sampling
* Periodic EOM-IP-CCSD and EOM-EA-CCSD for single k-point calculation
* spin-square value (per unit) of KUHF calculation
* Update interface to fciqmc for standalone executing
* Routines in fciqmc to read in the spinned one and two RDMs
* Heat-Bath CI
* Functions in dmrgci interface to access 3-pdm and 4-pdm
* Function get_fermi
* UCCSD lambda equation and 1,2-particle density matrix
* SCF wfn stability analysis
* Many-Body van der Waals Interactions (MBD)
* Second order SCF solver for periodic HF and DFT
* TDDFT for periodic k-point HF and DFT
* U-TDHF and U-TDDFT for molecular and crystal systems
* Many-body dispersion
* MP2-F12 and F12 basis and F12 RI basis
* Cartesian GTO (6d 10f) basis in molecular calculations
* CP2K's HF pseudopotential data
* Frozen core MP2
* Molecular electrostatic potential (MEP)
* CPHF and UCPHF solver
* Non-relativistic RHF, UHF 4-component UHF spin-spin coupling
* Generalized Hartree-Fock (GHF)
* Second order SCF solver for GHF
* non-relativistic UHF, UKS g-tensor
* non-relativistic UHF, UKS hyperfine coupling
* SHCI interface to Dice program
* spin-orbital CISD
* UCISD and UCISD 1- and 2-RDM
* Restricted CC2 method
* Density-fitting CCSD
* Heat-bath selected CI (HCI) spin-orbital 1- and 2-RDM
* "scanner" function for HF, DFT and CCSD to simplify energy or gradients
scanning for systems of different geometry.
* Interface to pyberny geometry optimizer (geometry optimization for RHF, RKS
and RCCSD are supported).
Improvements:
* Performance of PBC-Gaussian function evaluator
* Performance of analytical Fourier transformation for AO product
* Performance of PBC 3-center integrals
* Performance of PBC PP local-part integrals
* Numerical stability associated to OpenMP reduce function
* Performance of FCI 2-electron contraction function
* Basis parser for Pople style basis sets
* Arbitrary problem size in FCI solver
* Symmetry labels in orbital coefficients
* Disk usage of integral transformation in MP2
* Performance of J/K contractions in molecular density fitting code
* Input geometry parser for ghost atoms
* U-CCSD(T) performance
* ECP basis localization in Mulliken pop analysis
* Changing the CASCI/CASSCF default FCI solver (the default solver will not
use spin symmetry for singlet state)
* Supporting remove_linear_dep function to handle basis linear dependence in
k-point SCF
* cell.rcut estimation for better integral accuracy
* Convergence rates of PM localization
* MP2 and RCISD integral transformation performance
* Disk usage of CCSD-DIIS
* Input basis parser to support union basis set (eg mol.basis=(bas1,bas2))
* SCF initial guess for systems with pseudopotential (or ECP)
* SCF initial guess for low-dimension PBC systems
* Kinetic energy cutoff estimation
* Density fitting default auxiliary basis
* Memory usage for FFTDF module
* libxc interface
See also the [release notes](https://github.com/sunqm/pyscf/blob/master/doc/whatsnew/1.4.rst)
This release contains contributions from:
Qiming Sun, Lucas K. Wagner, James D. McClain, Timothy Berkelbach, Alexander Sokolov, jim, Bastien Mussard, Jan Hermann, Mark J. Williamson, Mark Williamson, Kevin Koh, Susi Lehtola, Sandeep Sharma, januseriksen, James Smith, George Booth,