# 8.2 Built-In Basis Sets

Q-Chem is equipped with many standard basis sets,13 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 96, 318, 231, 232, 233, 308

• Dunning basis sets 439

• Correlation consistent Dunning basis sets 440, 1004, 1005, 990, 486, 49

• Ahlrichs basis sets 804

• Jensen polarization consistent basis sets 421

• Karlsruhe "def2" basis sets 35, 455, 804, 554, 961, 767

• The universal Gaussian basis set (UGBS) 214

In addition, Q-Chem supports the following features:

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

• Standard polarization functions.

• Basis sets are requested by symbolic representation.

• $s$, $p$, $sp$, $d$, $f$, $g$ 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.

The following \$rem keyword controls the basis set:

BASIS
Sets the basis set to be used
TYPE:
STRING
DEFAULT:
No default basis set
OPTIONS:
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
RECOMMENDATION:
Consult literature and reviews to aid your selection.