Changes to default behavior:
Tightened default integral threshold (THRESH) to SCF_CONVERGENCE + 4 and used same threshold for DIIS and GDM
Set default of FD_MAT_VEC_PROD to FALSE for VV10 functional (Yuezhi Mao)
Turned off automatic evaluation of electrostatic potentils on a grid (Felix Plasser)
Set finite difference as default for energy derivatives in electric field (Yuezhi Mao)
General features and improvements:
Next-generation interface of Q-Chem with external tools (generation of archive files in the HDF5 format)
Implemented the nuclear-electronic orbital CCSD (NEO-CCSD) method (Fabijan Pavosevic, Sharon Hammes-Schiffer)
Implemented NEO-TDDFT analytical gradient and Hessian (Zhen (Coraline) Tao, Patrick E. Schneider, Sharon Hammes-Schiffer)
Enabled subset selection of atoms in NMR J-coupling calculations (JOBTYPE = ISSC) via spin input section
Disabled steepest descent in geometry optimization with fixed atoms
Added delocalized natural internal coordinate optimization in new optimizer
Updated geometry in the MOLDEN file for each step in finite difference optimizations (John Herbert)
Stabilized density fitting for JK and MP2
Set new optimizer as default for unconstrained optimization (GEOM_OPT_DRIVER = 2022)
Added the minimal-augmented and heavy-augmented versions of the Karlsruhe basis sets (John Herbert)
Removed MPI support
Resolved issues with:
incorrect Hirshfeld charges based on molecule input orders (Abdulrahman Aldossary)
not-a-number (NAN) errors in SOC calculations
missing nuclear repulsion energies in Fock projection (BASIS2) calculations
removed restriction on number of atoms (MAX_ATOM) that can be included in random search and basin hopping
ordering of localized MOs in formatted checkpoint files (Abdulrahman Aldossary)
missing ECP for the def2-SVPD basis set
failure to compute NMR properties with linearly dependent basis sets
parsing input files with 100k+ lines
character table of C3 point group
Density functional theory and self-consistent field:
Accelerated convergence of the SCF algorithm ADIIS and add a new combined algorithm option ADIIS_DIIS. (Yuezhi Mao)
Enabled gauge-independent atomic orbitals (GIAOs) in SCF calculations using GEN_SCFMAN (Brad Ganoe, Tim Neudecker, Joonho Lee, Adam Rettig, Jonathan Wong)
Disabled user setting of coefficients (via HFK_LR_COEF/HFK_SR_COEF) if using built-in range-separated functionals
Implemented frequency calculation and analytic Hessian for the VV10 functional (Jiashu Liang)
Enabled generation of formatted checkpoint files in CIS/TDDFT calculations with frozen occupied/virtual orbitals via GUI = 2 (Yuezhi Mao)
Enabled STATE_ANALYSIS for the new plot section (PLOT = 1) (Yuezhi Mao)
Performed consistency check on TDKS Fock matrices based on the SCF convergence threshold (SCF_CONVERGENCE) instead of the field amplitude (John Herbert)
Added new energy density functionals: revSCAN, regSCAN, r++SCAN, r2SCAN, r4SCAN, TASK, mTASK, regTM, rregTM, revTM
Enabled computing spin-orbit couplings (SOC) (1-electron and 2-electron mean-field) with TDDFT (both restricted and unrestricted) and spin-flip TDDFT (SF-TDDFT) (Saikiran Kotaru, Ana Krylov)
Implemented analytic gradient for density-corrected DFT (DC-DFT) for self-interaction correction (Marc Coons, Bhaskar Rana, John Herbert)
Resolved issues with:
incorrect results of fractional electron SCF calculations using GEN_SCFMAN (Yuezhi Mao)
hanging qints (USE_LIBQINTS = true) jobs with large number of OpenMP threads
non-variational initial SCF guess for ADIIS (Yuezhi Mao)
incorrect memory estimation in TDDFT/TDA calculations
crash of TDA excited state frequency jobs
crash of geometry optimization with fixed atoms
frequency calculations using basis functions with g or higher angular momenta
sign error with TDDFT spin-orbit coupling calculations (Nicole Bellonzi)
crash of projection-based embedding calculations (Yuezhi Mao)
incorrect result of RPA TDDFT frequency using non-Pople basis set
insufficient memory allocation for NMR calculations with meta-GGA functionals
erroneous results in DC-DFT calculations using hybrid functionals with larger basis sets (Marc Coons, Bhaskar Rana, John Herbert)
crash of excited state potential energy surface scans with CIS/TDDFT (John Herbert)
Correlated methods:
Implemented EOM oscillator strengths in velocity and mixed gauges (Josefine Andersen, Sonia Coriani)
Implemented CCSD optical rotation evaluation (Josefine Andersen, Kaushik Nanda)
Implemented the fragment charge difference (FCD) scheme in RASMAN2 (Chou-Hsun (Jeff) Yang, Aaditya Manjanath, Chao-Ping (Cherri) Hsu)
Implemented complex-valued CC2, RI-CC2, and RI-CCSD (Cansu Utku, Garrette Paran, Thomas Jagau)
Implemented the complex absorption potential (CAP) method in AIMD calculations (Jerryman A. Gyamfi, Thomas Jagau)
Implemented the v2RDM-CASSCF-PDFT method using density fitted basis sets (Mohammad Mostafanejad, Run Li, A. Eugene DePrince III)
Resolved formatting error in output of SOC calculation with RAS-CI method (Abel Carreras, David Casanova)
Molecular dynamics, non-adiabatic dynamics, embedding, and solvation:
Implemented projection-based embedding with complex basis functions (Valentina Parravicini, Thomas Jagau)
Enabled user-defined permittivity grid for Poisson equation solver (PEqS) (Suranjan Paul)
Improved PCM printing (John Herbert)
Implemented CIS and TDDFT wavefunction overlaps including their spin-flip variants for (A)FSSH (Theta Chen, Junhan Chen, Zuxin Jin, Vishikh Athavale, Vale Cofer-Shabica, Joe Subotnik)
Resolved issues with QM/MM optimzation not reading previous MOs as a guess for the next cycle
Fragment and energy decomposition analysis:
Implemented pairwise fragment excitation energy decomposition analysis (EDA) in QM/EFP calculations (Lyudmila Slipchenko)
Increased the maximum angular momentum of basis functions to 5 for XSAPT calculations
Implemented SPADE- and ALMO-based partitioning schemes for electric field calculations (Yuezhi Mao)
Implemented a new MP2 EDA scheme and added a non-perturbative polarization analysis for DFT EDA (Kevin Ikeda, Hengyuan Shen)
Enabled ALMO-CIS/TDA calculations with excitation amplitudes localized on one fragment (Yuezhi Mao)
Enabled ALMO-CIS/TDA calculations with excitation from one fragment’s occupied orbitals to all virtuals in the system (Yuezhi Mao)
Enabled ALMO-CIS/TDA calculations with excitation from one fragment’s occupied orbitals to another’s virtual orbitals (Yuezhi Mao)
Enabled user-defined occupied-virtual pairs in ALMO-CIS/TDA calculations (Yuezhi Mao)
Resolved miscellaneous issues with ALMO-CIS and excited-state ALMO-EDA calculations (Yuezhi Mao)
Miscellaneous:
Printed orbital kinetic energies using SCF_PRINT = 3
Enabled EXTERNAL_CHARGES specification in an external file (Vale Cofer-Shabica, Joseph Subotnik)
Added parameter check for many-body dispersion calculations (John Herbert)
Restored finite difference for wB97M2 and the XYG series of energy functionals
Restored finite difference banner for SA-SF-RPA