Q-Chem is equipped with many standard basis sets [458], and allows the user to specify the required basis set by its standard symbolic representation. The available built-in basis sets are of four types:

Pople basis sets

Dunning basis sets

Correlation consistent Dunning basis sets

Ahlrichs basis sets

Jensen polarization consistent basis sets

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.

, , , , and angular momentum types of basis functions.

Maximum number of shells per atom is 100.

Pure and Cartesian basis functions.

Mixed basis sets (see section 7.5).

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.