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8.2 Built-In Basis Sets

8.2.1 Overview

(February 4, 2022)

Q-Chem is equipped with many standard basis sets,11, B. P. Pritchard, D. Altarawy, B. Didier, T. D. Gibson, and T. L. Windus (2019) and allows the user to specify the required basis set by its standard symbolic representation. The available built-in basis sets include the following types:

  • Pople basis sets110, 385, 281, 282, 283, 373

  • Dunning basis sets293

  • Correlation-consistent (cc) Dunning basis sets, including:

    • Standard cc-pVXZ and aug-cc-pVXZ (X = D, T, Q, 5, and 6)294, 1234, 1220, 55

    • Partially-augmented “calendar” versions,857, 1289 may-, jun-, and jul-cc-pVXZ (X = D, T, Q)

    • Versions with core–valence polarization functions,924 cc-pCVXZ and cc-pwCVXZ (X = D, T, Q)

    • Partially-augmented core–valence polarization basis sets jun-, jul-, and aug-cc-pCVXZ (X = D, T, Q)

    • Pseudopotential (PP) basis sets for heavy elements, cc-pVXZ-PP and aug-cc-pVXZ-PP (X = D, T, Q)884, 885, 467

  • Ahlrichs basis sets993

  • Karlsruhe “def2” basis sets,1187 including

    • Augmented versions,946 such as def2-SVPD

    • Partially-augmented versions,Gray:2022 such as def2-ha-SVP and def2-ha-SVP

  • Jensen polarization consistent basis sets518, 519, 520

  • Universal Gaussian basis set (UGBS)256

In addition, Q-Chem supports the following features:

  • Extra diffuse functions available for high quality excited-state calculations.

  • Standard polarization functions.

  • s, p, sp, d, f, g and h angular momentum types of basis functions (for energy calculations, up to k are supported).

  • Pure and Cartesian basis functions.

  • Mixed basis sets (see Section 8.5).

  • Basis set superposition error (BSSE) corrections.

  • Automatic, on-the-fly generation of a superposition of atomic densities (SAD) guess for any basis set (including general and mixed basis sets) and any SCF level of theory (see Section 4.4.2).

The following $rem keyword controls the basis set:


       Sets the basis set to be used
       No default basis set
       General, Gen User-defined. See section below Symbol Use standard basis sets as in the table below Mixed Use a combination of different basis sets
       Consult literature and reviews to aid your selection.