FREEZE_CORE

Specifies how many core orbitals to freeze in correlated computations. TRUE or 1 will default to freezing the previous noble gas shell on each atom. In case of positive charges on fragments, an additional shell may be unfrozen, to ensure there are valence electrons in each fragment. With FALSE or 0, no electrons are frozen (with the exception of electrons treated by an ECP). With -1, -2, and -3, the user might request strict freezing of the previous first/second/third noble gas shell on every atom. In this case, when there are no valence electrons, the code raises an exception. More precise control over the number of frozen orbitals can be attained by using the keywords NUM_FROZEN_DOCC (gives the total number of orbitals to freeze, program picks the lowest-energy orbitals) or FROZEN_DOCC (gives the number of orbitals to freeze per irreducible representation) or by the option POLICY in combination with appropriate inputs to FREEZE_CORE_POLICY At present, POLICY is an experimental option and is subject to change.

• Type: string

• Possible Values: FALSE, TRUE, 1, 0, -1, -2, -3, POLICY

• Default: FALSE