23.1.1 The BRUECKNER directive

BRUECKNER,orbbrk,ibrstr,ibrueck,brsfak;

This directive allows the specification of options for Brueckner calculations. Normally, none of the options has to be specified, and the BCCD command can be used to perform a Brueckner CCD calculation.

orbbrk:

if nonzero, the brueckner orbitals are saved on this record.

ibrstr:

First iteration in which orbitals are modified (default=3).

ibrueck:

Iteration increment between orbital updates (default=1).

brsfak:

Scaling factor for singles in orbital updates (default=1).