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New Features in Q-Chem 4.1:

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.

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.