25.2.8 Occupation restrictions

RESTRICT,nmin,nmax,orb$_1$,orb$_2$,$\ldots$orb$_n$;

This card can be used to restrict the occupation patterns in the reference configurations. Only configurations containing between nmin and nmax electrons in the specified orbitals orb$_1$, orb$_2$, $\ldots$, orb$_n$ are included in the reference function. If nmin and nmax are negative, configurations with exactly abs(nmin) and abs(nmax) electrons in the specified orbitals are deleted. This can be used, for instance, to omit singly excited configurations. The orbitals are specified in the form number.sym, where number is the number of the orbital in irrep sym. Several RESTRICT cards may follow each other.

The RESTRICT cards must follow the WF or REF cards to which they apply. The general order of these cards is

WF (or REF)
RESTRICT (optional)
SELECT (optional)
CON (optional)

If a RESTRICT cards precedes the WF card, it applies to all reference symmetries. Note that RESTRICT also affects the spaces generated by SELECT and/or CON cards.