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New Features Added in Q-Chem 4.3:

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