1.3 Q-Chem Features

1.3.1 New Features in Q-Chem 5.4

(June 30, 2021)
  • Changes to default behavior:

    • Use of automatically generated superposition of atomic densities SCF guess for custom basis sets (Yuezhi Mao, Kevin Carter-Fenk)

    • Use atomic size-corrected Becke weights for CDFT (Kevin Carter-Fenk)

  • General features and improvements:

    • New methods to distort molecules using force and pressure: HCFF, X-HCFF, GOSTSHYP (Tim Stauch, Maximilian Scheurer)

    • Overhauled library of standard basis sets for consistency with Basis Set Exchange and extended support through element 118

    • Improved stability of ECP fitting and updated definitions of fitted ECPs (CRENBS, CRENBL, HWMB, LACVP, LANL2DZ, SBKJC)

    • Evaluation of electric field at nuclei (Yuezhi Mao)

    • Frequency calculations for rigid fixed-atom constraints (Saswata Dasgupta)

    • Save additional calculation output files to unique folder

    • Resolved issues with:

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        inconsistent application of quadrupole field to resolve orbital degeneracies

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        definition of jun-cc-pVDZ basis set (John Herbert)

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        some jobs crashing with the FILE_SET_SYM_REP read error

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        cleaning up in PES scan jobs on Windows

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        unnecessary gradient evaluation at every point of frozen PES scan

  • Features and improvements in density functional theory and self-consistent field:

    • Vibronic and resonance Raman spectroscopy (Xunkun Huang, Huili Ma, WanZhen Liang)

    • Integrated DFT-D4 empirical dispersion model (Kuan-Yu Liu, Romit Chakraborty)

    • New implementation of direct propagation of the time-dependent Kohn-Sham equation (real-time TDKS) with support for unrestricted SCF and implicit solvation (Ying Zhu, John Herbert)

    • State-targeted energy projection method (Kevin Carter-Fenk, John Herbert)

    • Multiple improvements to frozen-density embedding methods (Cristina González-Espinoza, Alexander Zech, Tomasz A. Wesolowski)

    • Faster algorithm for ωGDD tuning (John Herbert)

    • Improvements in the IP/EA omega tuning scripts for long range corrected functionals (John Herbert)

    • Support for high angular momentum in DFT frequency calculations

    • Superposition of atomic potentials (SAP) guess for SCF (Yu Zhang, Susi Lehtola)

    • Expand density functionals available for NMR chemical shift calculations (Jiashu Liang, Khadiza Begam, Barry Dunietz, Yihan Shao)

    • Nuclear gradient and analytical 2nd functional derivative of the VV10 functional (Jiashu Liang)

    • Performance improvements in the evaluation of DFT-D3 nuclear hessian contribution

    • Consistent constrained DFT and SCF convergence criteria (Kevin Carter-Fenk)

    • NVIDIA GPU computing improvements via interface with BrianQC:

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        Accelerated force and vibrational frequency computations with range-separated functionals

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        Accelerated Fock derivative computation in DFT vibrational frequency jobs

    • Resolved issues with:

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        buffer overflow in a special case of very large DFT jobs

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        a special case of crashing unrestricted CIS derivative coupling calculations

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        evaluation of finite-difference nonlocal correlation orbital Hessian (Yuezhi Mao)

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        use of AO integrals in general response module

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        differences in DFT quadrature between Linux and macOS

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        using ghost atoms in MBD-vdW calculations (Kevin Carter-Fenk, Evgeny Epifanovsky)

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        using arbitrary density functionals for MBD-vdW and TS-vdW

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        crashing large CIS state following calculations

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        SOC constants with unrestricted TDDFT

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        RI-J/RI-K gradient

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        DFT hyperpolarizabilities

  • Features and improvements in correlated methods:

    • Calculation of electronic g-tensors with CCSD (Sven Kähler, Anna Krylov);

    • Calculation of electronic circular dichroism (ECD) using EOM-CC (Josefine Andersen, Sonia Coriani)

    • Evaluation of spin-orbit couplings using CVS-EOM methods, L-edge XAS/XES spectroscopy calculations (Marta Vidal, Pavel Pokhilko, Sonia Coriani)

    • Feshbach method with EOM-CC states and Coulomb wave expanded in terms of plane wave Gaussian type orbitals (Wojciech Skomorowski)

    • Improved performance in small to medium CC/EOM jobs via in-core computations

    • Improvements in projected CAP EOM-CC (James Gayvert)

    • IP/EA-ADC methods and intermediate state representation (ISR) properties (Adrian Dempwolff, Matthias Schneider, Alexander Paul)

    • Dramatic speedup of ADC(3) (Adrian Dempwolff)

    • Improved fourth-order static self-energy for all ADC variants (PP (EE), IP, EA) (Adrian Dempwolff)

    • Subspace-projected CAP-ADC for all ADC variants (PP (EE), IP, EA) (Adrian Dempwolff)

    • Evaluation of spin-orbit couplings using RAS-CI and RAS2-SF methods (Abel Carreras, Anna Krylov, David Casanova, Hanjie Jiang, Pavel Pokhilko, Paul M. Zimmerman)

    • Use of resolution-of-the-identity integrals in LibRASSF-based implementation of RAS-SF (Shannon Houck)

    • Implementation of the Bloch effective Hamiltonian approach within LibRASSF-based RAS-SF (Shannon Houck)

    • Experimental implementation of the CC2 and RI-CC2 methods (Garrette Paran, Thomas Jagau)

    • Implementation of the Brueckner CC2 method (Adam Rettig)

    • Implementation of direct RPA for the ground state correlation energy (Joonho Lee)

    • Cubic storage RI-MP3 and Laplace-transformed RI-MP2/RI-MP3 (Joonho Lee)

    • Added access to κ-regularized orbital optimized MP2 via METHOD = koomp2

    • New implementation of v2RDM and v2RDM-CASSCF solvers (Rain Li, Wayne Mullinax, A. Eugene DePrince III, Marcus Liebenthal)

    • Improved defaults in incremental FCI (Alan Rask)

    • Experimental implementation of tensor hypercontraction methods (Joonho Lee)

    • Resolved issues with:

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        2 GB limit on temporary files in CC/EOM/ADC calculations on Windows

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        evaluation of analytic gradients of κ-regularized OO-MP2

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        crashing in fragment excitation difference (FED) calculations due to insufficient memory (Aaditya Manjanath)

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        crashing in large RI-MP2 calculations

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        initial guess in EOM-DIP-CCSD calculations

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        crashing in large RI-CCSD calculations

  • Features and improvements in molecular dynamics:

    • New AIMD variable (AIMD_INIT_VELOC_NANO_RANDOM) for better random seeds (Tarek Scheele)

    • Resolved issues with:

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        activating vibrational spectra computation in special cases

  • Features and improvements for large systems, QM/MM, and solvation:

    • AIRBED: A simplified density functional theory model for physisorption on surfaces (Nick Besley, Stephen Mason)

    • Resolved issues with:

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        SM12 crashes with general basis set (Yuezhi Mao)

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        MM finite difference force calculations

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        printing of EFG principal components

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        SM12 gradient

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        implicit solvation in SCF and DFT response property calculations

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        requiring explicit derivative level to be set for IEF-PCM frequencies (John Herbert)

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        RI-MP2 + PCM jobs

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        out-of-memory error in large SMD jobs

  • Features and improvements for fragment and energy decomposition analysis methods:

    • Enable geometry optimization on POL and VFB-CT surfaces in the presence of solvent (Yuezhi Mao)

    • Enable ALMO-EDA for systems with non-Aufbau electronic configurations (Yuezhi Mao)

    • Enable the separation of electrostatic and non-electrostatic terms in SMD solvation energy (Yuezhi Mao)

    • Improve error message when attempting ROHF-based SCFMI and EDA

    • Improve error message when attempting to use unsupported solvent models with SCFMI and EDA

    • Control number of subspace vectors and convergence threshold in SAPT CPSCF (Kevin Carter-Fenk)

    • Improved SAPT+aiDX and SAPT+MBD keywords (Kevin Carter-Fenk)

    • Resolved issues with:

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        crashing during large projection-based embedding calculations (Yuezhi Mao)

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        requiring explicit derivative level to be set for adiabatic EDA geometries and frequencies (Yuezhi Mao)

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        interoperability between SAPT features and various SAPT basis sets (Kevin Carter-Fenk)

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        crashing when using SAPT(KS) + cDFT with fragment-based Hirshfeld populations (Kevin Carter-Fenk)

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        memory usage in XSAPT (Kevin Carter-Fenk, John Herbert)