Release Log for Q-Chem 6.0


Q-Chem 6.0.1 Release

August 24, 2022

Changes to default behavior

  • Restored support for IGDESP used by CHARMM (John Herbert)
  • Implemented a memory-efficient GOSTSHYP algorithm (Felix Zeller)
  • Enabled finite-field chemical shielding and magnetizability calculations using gauge-independent atomic orbitals (GIAOs) for HF and MP2 (Jonathan Wong, Brad Ganoe, Tim Neudecker, Adam Rettig, Xiao Liu, Joonho Lee)
  • Resolved issues with:
    • molden output for optimization in libopt3
    • libopt3 Hessian calculations using PCM
    • writing MO coefficients and energies to qarchive file
    • cleaned up topology checking printing
    • fixed printing of RMS of step size during geometry optimization

Molecular dynamics, non-adiabatic dynamics, embedding, and solvation

  • Implemented state-specific PCM with RAS-SF (Bushra Alam, Hanjie Jiang, John Herbert, Paul Zimmerman)

Fragment and energy decomposition analysis

  • Resolved issues with projection-based embedding calculations where frozen (environment) occupied orbitals are not ordered based on energies (Yuezhi Mao)


  • Added comments to DFT SOC calculations for identifying the progress of the job (Saikiran Kotaru)
  • Added warning about not having analytic Hessians for some optimization jobs
  • Added printing to distinguish CPCM1 from CPCM2

Q-Chem 6.0.0 Release

July 3, 2022

Changes to default behavior

  • Tightened default integral threshold ($rem variable 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 potentials on a grid (Felix Plasser)
  • Set finite difference as default for second 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 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)
  • Implemented projection-based embedding with complex basis functions (Valentina Parravicini, Thomas Jagau)
  • 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)
  • 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 issues with:
    • formatting error in output of SOC calculation with RAS-CI method (Abel Carreras, David Casanova)

Molecular dynamics, non-adiabatic dynamics, embedding, and solvation

  • 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)


  • 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

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