20.2.1 Occupied orbitals

OCC, $n_1,n_2,\ldots,n_8$;

$n_i$ specifies numbers of occupied orbitals (including CORE and CLOSED) in irreducible representation number $i$. In the absence of an OCC card, the information from the most recent MCSCF calculation is used, or, if there is none, those orbitals corresponding to a minimal valence set, i.e., full valence space, are used.