8.2.1 Overview

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 sets ¹²⁹ Binkley J. S., Pople J. A., Hehre W. J.
  J. Am. Chem. Soc.
  (1980), 102, pp. 939. Link ^{, 453} Gordon M. S. et al.
  J. Am. Chem. Soc.
  (1982), 104, pp. 2797. Link ^{, 331} Dobbs K. D., Hehre W. J.
  J. Comput. Chem.
  (1986), 7, pp. 359. Link ^{, 332} Dobbs K. D., Hehre W. J.
  J. Comput. Chem.
  (1987), 8, pp. 861. Link ^{, 333} Dobbs K. D., Hehre W. J.
  J. Comput. Chem.
  (1987), 8, pp. 880. Link ^{, 440} Glendening E. D., Feller D.
  J. Phys. Chem.
  (1995), 99, pp. 3060. Link

• •

  Dunning basis sets ³⁴³ Dunning Jr. T. H.
  J. Chem. Phys.
  (1971), 55, pp. 716. Link

• •

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

  • –

    Standard cc-pVXZ and aug-cc-pVXZ (X = D, T, Q, 5, and 6) ³⁴⁴ Dunning Jr. T. H.
    J. Chem. Phys.
    (1989), 90, pp. 1007. Link ^{, 1427} Woon D. E., Dunning Jr. T. H.
    J. Chem. Phys.
    (1993), 98, pp. 1358. Link ^{, 1410} Wilson A. K. et al.
    J. Chem. Phys.
    (1999), 110, pp. 7667. Link ^{, 67} Balabanov N. B., Peterson K. A.
    J. Chem. Phys.
    (2005), 123, pp. 064107. Link

  • –

    Partially-augmented “calendar” versions, ⁹⁹⁶ Papajak E., Truhlar D. G.
    J. Chem. Theory Comput.
    (2011), 7, pp. 10. Link ^{, 1499} Zheng E. Papajak J. et al.
    J. Chem. Theory Comput.
    (2011), 7, pp. 3027. Link may-, jun-, and jul-cc-pVXZ (X = D, T, Q)

  • –

    Versions with core–valence polarization functions, ¹⁰⁷⁶ Prascher B. P. et al.
    Theor. Chem. Acc.
    (2011), 128, pp. 69. Link 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) ¹⁰³⁴ Peterson K. A. et al.
    J. Chem. Phys.
    (2003), 119, pp. 11113. Link ^{, 1035} Peterson K. A., Puzzarini C.
    Theor. Chem. Acc.
    (2005), 114, pp. 283. Link ^{, 556} Hill J. G., Peterson K. A.
    J. Chem. Phys.
    (2017), 147, pp. 244106. Link

• •

  Ahlrichs basis sets ¹¹⁵⁴ Schäfer A., Horn H., Ahlrichs R.
  J. Chem. Phys.
  (1992), 97, pp. 2571. Link

• •

  Karlsruhe “def2” basis sets, ¹³⁷⁴ Weigend F., Ahlrichs R.
  Phys. Chem. Chem. Phys.
  (2005), 7, pp. 3297. Link including

  • –

    Augmented versions, ¹¹⁰¹ Rappoport D., Furche F.
    J. Chem. Phys.
    (2010), 133, pp. 134105. Link such as def2-SVPD

  • –

    Partially-augmented versions, ⁴⁶¹ Gray M., Herbert J. M.
    J. Chem. Theory Comput.
    (2022), 18, pp. 2308. Link such as def2-ha-SVP and def2-ha-SVP

• •

  Jensen polarization consistent basis sets ⁶¹⁶ Jensen F.
  J. Chem. Theory Comput.
  (2008), 4, pp. 719. Link ^{, 617} Jensen F.
  Theor. Chem. Acc.
  (2010), 126, pp. 371. Link ^{, 618} Jensen F.
  J. Chem. Theory Comput.
  (2014), 10, pp. 1074. Link

• •

  Universal Gaussian basis set (UGBS) ³⁰² de Castro E. V. R., Jorge F. E.
  J. Chem. Phys.
  (1998), 108, pp. 5225. Link

In addition, Q-Chem supports the following features:

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

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  Standard polarization functions.

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

• •

  Pure and Cartesian basis functions.

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  Mixed basis sets (see Section 8.5).

• •

  Basis set superposition error (BSSE) corrections.

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  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: