1.3 Q-Chem Features

1.3.4 New Features in Q-Chem 4.4

  • occ-RI-K algorithm for the evaluation of exact exchange in energy and force calculations (S. Manzer, F. Rob and M. Head-Gordon; Section 4.6.9)

  • Combinatorially-optimized exchange-correlation functionals (N. Mardirossian and M. Head-Gordon; Section 5.3):

    • ωB97M-V (range-separated hybrid, meta-GGA functional with VV10 non-local correlation)

    • B97M-V (meta-GGA functional with VV10 non-local correlation)

    • ωB97X-V (range-separated hybrid functional with VV10 non-local correlation)

  • Implementation of new exchange-correlation functionals from the literature (N. Mardirossian and M. Head-Gordon; Section 5.3). These include:

    • MGGA_MS0, MGGA_MS1, MGGA_MS2, MGGA_MS2h, MGGA_MVS, MGGA_MVSh, PKZB, revTPSS, revTPSSh, SCAN, SCAN0, PBEsol, revPBE, revPBE0

    • N12, N12-SX, GAM, MN12-L, MN12-SX, MN15-L, dlDF

    • VV10, LC-VV10

    • B97-K, B97-D3(0), B97-3, τ-HCTH, τ-HCTHh

    • SRC1-R1, SRC1-R2, SRC2-R1, SRC2-R2

    • B1LYP, B1PW91, MPW1K, LRC-BOP, BHH, BB1K, PW6B95, PWB6K, B2PLYP

  • Hessian-free minimum point verification (S. M. Sharada and M. Head-Gordon; Section 10.2.2)

  • Exciton-based excited-state models:

    • Ab initio Frenkel-Davydov model for coupled excitations in multi-chromophore systems (A. F. Morrison and J. M. Herbert; Section 13.16).

    • TDDFT for molecular interactions [TDDFT(MI)], a set of local excitation approximations for efficient TDDFT calculations in multi-chromophore systems and for single chromophores in the presence of explicit solvent molecules (J. Liu and J. M. Herbert; Section 13.17).

  • Improvements to many-body and XSAPT methods (K. U. Lao and J. M. Herbert)

    • MPI-parallelized many-body expansion with analytic gradient (Section 13.15).

    • Efficient atomic orbital implementation of XSAPT for both closed- and open-shell systems (Section 13.13.2).

  • Thermostats for ab initio molecular dynamics (R. P. Steele and J. M. Herbert).

  • Analytic energy gradient for the Ewald summation in QM/MM calculations (Z. C. Holden and J. M. Herbert)

  • Zeolite QM/MM methods (J. Gomes and M. Head-Gordon).

  • EOM-MP2 methods for excitation, ionization and electron attachment energies (A. Kunitsa and K. Bravaya; Section 7.8.9).

  • Evaluation of polarizabilities using CCSD and EOM-CCSD wave functions (Section 7.8.16.4, K. Nanda and A. I. Krylov)

  • Distributed-memory parallel implementation of CC and EOM-CC methods and performance improvements in disk-based algorithms (E. Epifanovsky, I. Kaliman, and A. I. Krylov)

  • Improvements to the maximum overlap method (MOM) for SCF calculations (A. T. B. Gilbert; Section 7.5).

  • Non-equilibrium PCM method to describe solvent effects in ADC excited-state calculations (J.-M. Mewes and A. Dreuw; Section 7.9.7).

  • Spin-flip ADC method (D. Lefrancois and A. Dreuw; Section 7.9.5).