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New Features in Q-Chem 4.4


Download Q-Chem 4.4

Q-Chem 4.4.0 (released May 2016):

  • OCC-RI-K algorithm for the evaluation of exact exchange in energy and force calculations

  • Combinatorially-optimized exchange-correlation functionals:

    • wB97M-V (range-separated hybrid, meta-GGA functional with VV10 nonlocal correlation)

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

    • wB97X-V (range-separated hybrid functional with VV10 nonlocal correlation)

  • Implementation of new exchange-correlation functionals from the literature, including:


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

    • VV10, LC-VV10

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

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


  • Hessian-free minimum point verification

  • Exciton-based excited-state models:

    • Ab initio Frenkel-Davydov model for coupled excitations in multi-chromophore systems.

    • 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.

    Improvements to many-body and XSAPT methods

    • MPI-parallelized many-body expansion with analytic gradient. <

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

  • Thermostats for ab initio molecular dynamics.

  • Analytic energy gradient for the Ewald summation in QM/MM calculations.

  • Zeolite QM/MM methods.

  • EOM-MP2 methods for excitation, ionization and electron attachment energies.

  • Evaluation of polarizabilities using CCSD and EOM-CCSD wave functions.

  • Distributed-memory parallel implementation of CC and EOM-CC methods and performance improvements in disk-based algorithms.

  • Improvements to the maximum overlap method (MOM) for SCF calculations.

  • Non-equilibrium PCM method to describe solvent effects in ADC excited-state calculations.

  • Spin-flip ADC method.

    New Features Added in Q-Chem 4.3:

    Q-Chem 4.3.2 (released December 2015):

    • More effective parallel implementation of VV10 XC calculations using OpenMP

    • Implemented QCISD(T) method in CCMAN2 module

    • Improved stability of GVB and PP calculations

    • Resolved an integer overflow issue in file IO causing Q-Chem to crash when reading and writing very large files (file size exceeding 2GB)

    • Fixed an error in analytical frequency calculations involving GGA functionals with Gab crossing term, e.g., P86, PW91 and PBE functionals

    • Resolved issues with basis set superposition error calculations involving Grimme's D3 correction

    • Fixed a bug which leads to erroreous MOS-MP2 energy

    • Resolved an issue causing Q-Chem to crash upon startup on certain Linux distributions

    • Fixed a memory leak in the SCF procedure leading to increased memory consumption in large optimization and finite difference calculations

    • Fixes in the wavefunction analysis module

    Q-Chem 4.3.1 (released August 2015):

    • Streamlined implementation of density functional derivative computations;

    • New implementation of Dyson orbital computation with real and complex CC/EOM methods;

    • Properties calculations and density plotting with complex CC/EOM methods;

    • Parallelization of computations using omegaB97X-D3, omegaM05-D, omegaM06-D3, AK13, LFAs, TAO-DFT;

    • Enabled gradient computation with direct TDDFT/RPA bypassing TDDFT/TDA;

    • Several improvements in TAO-DFT.

    For a complete listing please read the release log here.

    Q-Chem 4.3.0 (released May 2015):

    • Analytic derivative couplings (i.e. nonadiabatic couplings) between electronic states computed at the CIS, spin-flip CIS, TDDFT, and spin-flip TDDFT levels;

    • A third-generation +D3 dispersion potential for XSAPT;

    • Non-equilibrium PCM for computing vertical excitation energies and ionization potentials in solution;

    • Spin-orbit couplings between electronic states for CC and EOM-CC wavefunctions;

    • The PARI-K method for evaluation of exact exchange yields dramatic speedups for TZ and greater basis set hybrid DFT calculations;

    • Transition moments and cross sections for two-photon absorption using EOM-CC wave functions;

    • New excited-state analysis for ADC and CC/EOM-CC methods;

    • New Dyson orbital code for EOM-IP-CCSD and EOM-EA-CCSD;

    • Thermally-Assisted-Occupation Density Functional Theory (TAO-DFT);

    • MP2[V], a dual basis method that approximates the MP2 energy;

    • LFAs asymptotic correction scheme for semilocal exchange-correlation functionals;

    • Shared-memory parallelization of TDDFT energy and gradient calculations;

    • wM05-D, wM06-D3, and wB97X-D3 long-range corrected hybrid functionals with dispersion corrections;

    • PBE0-2 and PBE0-DH parameter-free double-hybrid functionals;

    • Derivative discontinuity restoration scheme for energy gap correction;

    For a complete listing please read the release log here

    Features Added in Q-Chem 4.2:

    Q-Chem 4.2.2 (released December 2014):

    • Extended complex-absorbing-potential (CAP) calculation to use unrestricted wavefunctions (CAP-UHF and CAP-UCCSD)

    • Enabled CAP calculations based on EOMIP-CCSD and EOMSF-CCSD methods

    • Enabled direct RPA and TDDFT calculations (RPA=2) without going through CIS or TDDFT/TDA calculations first

    • OpenMP implementation for 1-E integral computing and improved hybrid MPI/OpenMP performance

    • License scheme checking IP address

    • Updated libefp module to allow Cartesian coordinates (xyz format) specification for fragments consisting of less than 3 atoms

    • Multiple improvements in complex-scaled (CS) and complex-absorbing-potential (CAP) coupled-cluster and equation-of-motion methods

    • Enabled printing orbitals in MOLDEN format at each step of AIMD

    • Allow ranges to be used in "$occupied" and "$qm_atom" input sections

    • Enabled the use of LANL2DZ-SV basis set in conjunction with LANL2DZ effective core potentials.

    For a complete listing please read the release log here.

    Q-Chem 4.2.1 (released August 2014):

    • Linearized CCD (LCCD) method;

    • ADC(3) method;

    • New feature to request a PCM calculation using a single, spherical cavity;

    • COSMO radii for many transition metal elements;

    • PCM solvation is now supported for systems involving effective core potentials;

    • Density embedding now calculates 1-in-2 + 2-in-1 in a single job;

    • Improvements in the wB97 family density functionals;

    • Interface with NBO5 improved for orbital and density visualization;

    • Cleaned-up and unified input keywords for implicit solvation models (also see Q-Chem manual).

    For a complete listing please read the release log here.

    Q-Chem 4.2.0 (released May 2014):

    • QM/MM interface for modeling Zeolites;

    • SM12 implicit solvation model;

    • NBO 6 interface;

    • Simplified input for method, excited states and solvation model specification;

    • Complex scaling and complex absorbing potential approaches for EOM-CC;

    • Restricted Open-shell Kohn-Sham Method for excited states calculation;

    • Derivative coupling between CIS excited states;

    • Pseudo-fractional occupation number method for improved SCF convergence in small-gap systems;

    • Density embedding calculations allowing fragments to be treated at different levels of quantum mechanics;

    • Pair RI fitting algorithm for fast exchange Fock matrix computing in HF/DFT;

    • New methods and enhancements in fragment-based many-body expansion methods;

    • Hybrid MPI/OpenMP implementation for HF/DFT energy and gradient.
    For a complete listing please read the release log here.

    Features Added in Q-Chem 4.1:

    Q-Chem 4.1.2 (released February 2014):

    • Added OpenMP implementation for DFT with pure and range-separated functionals;

    • Added Coulomb screening and other performance enchancements for OpenMP code;

    • Added XSAPT+D;

    • Enabled TDDFT calculations with SOGGA11 and SOGGA11X;

    • added wB97X-V functional

    • enabled gaussian blur with ECP

    • enabled PCM using ECP

    • enabled ccman2 EOM CCSD(T)

    • added minimum energy crossing point (MECP) calculation with spin-flip TDDFT

    • added minimum energy crossing point (MECP) calculation with spin-flip TDDFT

    • added CIS-to-CIS derivative coupling

    For a complete listing please read the release log here.

    Q-Chem 4.1.1 (released October 2013):

    • Performance improvement and parallelization of Effective Fragment Potential calculation

    • addded new EFP features, E.g., polarization damping, overlap-based damping

    • store unrelaxed and relaxed one particle density matrix for coupled-cluster and equation-of-motion coupled-cluster wavefunction analysis

    • added Truhlar's SM12 model

    • enabled cutting of non C-C bonds in internal QM/MM calculations

    • added excitation energy decomposition with wB97X and wB97X-D functionals

    • Implemented QACF

    For a complete listing please read the release log here.

    Q-Chem 4.1 (released July 2013):

    • Improved parallel performance at all levels including new OpenMP capabilities for SCF/DFT, MP2, integral transformation and coupled cluster theory;

    • Significantly enhanced ECP capabilities,especially for gradient and frequency calculations;

    • TDDFT energy calculation with M06, M08 and M11-series of functionals;

    • Enhancement to the freezing string method, especially the construction of approximate hessian for transition state structure refinement;

    • XYGJ-OS analytical energy gradient;

    • TDDFT/C-PCM excitation energies, gradient, and Hessian;

    • RI/Cholesky decomposition implementation of CCSD and EOM-CCSD enabling application to larger systems;

    • Attenuated MP2 theory with much more accurate results than MP2 for intermolecular interactions;

    • Extended RAS-nSF for studying excited states;

    • Potential energy scan;

    • Automatic transition structure search algorithms by the freezing string method with approximate Hessian;

    • fEFP method extending EFP to macromolecules;

    • Extension of the ALMO/EDA to unrestricted cases;

    • Symmetry-adapted perturbation theory for intermolecular interaction energy decomposition analysis;

    • XPol monomer-based SCF calculations of many-body polarization effects in linear-scaling time;

    • A new method of evaluating localized atomic magnetic moments and correlated bond orders within DFT;

    • T-Chem quantum transport code implementing state of the art description of the non-equilibrium conditions affecting the molecular bridge;
    • Searchable online version of our pdf manual (coming soon); and

    • Many other features.

    For a complete listing please read the release log here.

    Features Added in Q-Chem 4.0:


    Q-Chem 4.0.1 (released October 2012):

    • Remote job submission in IQmol;

    • High performance OpenMP implementation of coupled-cluster and EOM-CC methods;

    • TDDFT gradient extended to more functionals, such as wPBE, wPBEh and CAM-B3LYP;

    • Grimme's B97-D functional, popular for studying dispersion interactions;

    • New functionals, e.g., self-consistent RI-B05 and RI-PSTS, for studying strongly correlated chemical systems;

    • Calculations of excited state properties including transition dipole moments between different excited states in CIS and TDDFT as well as couplings for electron and energy transfer;

    • Scaled nuclear charge and charged cage stabilization capabilities;

    • Manual is updated to include more input examples;

    • The sample input files are reorganized following the new naming convention. They are also categorized into subdirectories for easy browsing;

    • The new online installer provides a simpler way to help you get started. The new package maintenance module in 4.0.1 brings upgrading to your fingertips;
    For a complete listing please read the release log here.

    Q-Chem 4.0 (released February 2012):

    • DFT Algorithms

      • Fast numerical integration of exchange-correlation with mrXC (multiresolution exchange-correlation) Shawn Brown, Laszlo Fusti-Molnar, Nicholas J. Russ, Chun-Min Chang, Jing Kong, Section 4.4.7).

      • Efficient computation of the exchange-correlation part of the dual basis DFT (Zhengting Gan, Jing Kong, Section 4.5.5).

      • Fast DFT calculation with ‘triple jumps’ between different sizes of basis set and grid and different levels of functional (Jia Deng, Andrew Gilbert, Peter M. W. Gill, Section 4.8).

      • Faster DFT and HF calculation with atomic resolution of the identity (ARI) algorithms (Alex Sodt, Martin Head-Gordon.)

    • POST-HF: Coupled Cluster and Equation of Motion

      • Significantly enhanced coupled-cluster code rewritten for better performance and multicore systems for many modules (energy and gradient for CCSD, EOM-EE/SF/IP/EACCSD, CCSD(T) energy). (Evgeny Epifanovsky, Michael Wormit, Tomasz Kuz, Arik Landau, Dmitri Zuev, Kirill Khistyaev, Ilya Kaliman, Anna Krylov, Andreas Dreuw, Chapters 5 and 6 (the new code is named CCMAN2).

      • Fast and accurate coupled-cluster calculations with frozen natural orbitals (Arik Landau, Dmitri Zuev, Anna Krylov, Section refsec: FNOCC).

    • POST-HF: Strong Correlation

      • Perfect Quadruples and Perfect Hextuples methods for strong correlation problems (John Parkhill, Martin Head-Gordon, Section 5.6.1).

      • Coupled Cluster Valence Bond (CCVB) and related methods for multiple bond breaking (David Small, Keith Lawler, Martin Head-Gordon, Section 5.13).

    • DFT Excited States and Charge Transfer

      • Nuclear gradients of excited states with TDDFT (Yihan Shao, Fenglai Liu, Zhengting Gan, Chao-Ping Hsu, Andreas Dreuw, Martin Head-Gordon, Jing Kong, Section 6.3.1).

      • Direct coupling of charged states for the study of charge transfer reactions (Zhi-Qiang You, Chao-Ping Hsu, Section 10.17.2).

      • Analytical excited-state Hessian in TDDFT within Tamm-Dancoff approximation (Jie Liu, Wanzhen Liang, Section 6.3.5).

      • Obtaining an excited state self-consistently with MOM (maximum overlap method) (Andrew Gilbert, Nick Besley, Peter M. W. Gill, Section 6.5).

      • Calculation of reactions with configuration interactions of charge-constrained states with constrained DFT (Qin Wu, Benjamin Kaduk, Troy Van Voorhis, Section 4.9).

      • Overlap analysis of the charge transfer in a excited state with TDDFT (Nick Besley, Section 6.3.2).

      • Localizing diabatic states with Boys or Edmiston-Ruedenberg localization scheme for charge or energy transfer (Joe Subotnik, Ryan Steele, Neil Shenvi, Alex Sodt, Section

    • Wavefunction-Based Excited States

    • Analytical Tools

      • Analysis of metal oxidation states via localized orbital bonding analysis (Alex Thom, Eric Sundstrom, Martin Head-Gordon, Section 10.3.4).

      • Improved robustness of IRC code (intrinsic reaction coordinate following) (Martin Head-Gordon).

      • Hirshfeld population analysis (Sina Yeganeh, Section 10.3.1).

      • Visualization of noncovalent bonding using Johnson and Yang’s algorithm (Yihan Shao, Section 10.9.5).

      • ESP on a grid for transition density (Yihan Shao, Section 10.10).

    • Support for Modern Computing Platforms

      • Better performance for multicore systems with shared-memory parallel DFT/HF (Zhengting Gan, Yihan Shao, Jing Kong) and RI-MP2 (Matthew Goldey, Martin Head-Gordon)(Section 5.12).

      • Accelerating RI-MP2 calculation with GPU (graphic processing unit) (Roberto Olivares-Amaya, Mark A. Watson, Richard G. Edgar, Leslie Vogt, Yihan Shao, Alan Aspuru-Guzik, Section 5.5.3).

    • Graphic User Interface

      • Support of new IQmol, a free GUI designed by Andrew Gilbert at Australian National University. For more information on IQmol, visit www.iqmol.org.

    More details on the features of Q-Chem 4 can be found in the Version 4 User's Guide.