MOLPRO

19 THE MCSCF PROGRAM MULTI 130
f) configuration specification for that state symmetry – SELECT,CON,RESTRICT
g) definition of the primary configurations for that state symmetry - PSPACE
h) further general options
Stages d) through to h) may be repeated several times; this is the way in which you specify an
average energy of several states of different symmetry.
Many options can be specified on the MULTI command line:
MULTI,options
Selected options:
MAXIT Max. number of iterations (default 10)
ENERGY
GRADIENT
STEP
FAILSAFE
Convergence threshold for energy
Convergence threshold for gradient
Convergence threshold for steplength
(logical) Use options for more robust convergence
Many further options and thresholds, which can also be given on the command line, are described
in section 19.8.5.
19.2 Defining the orbital subspaces
19.2.1 Occupied orbitals
OCC,n 1 ,n 2 ,...,n 8 ;
n i specifies numbers of occupied orbitals (including FROZEN 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.
19.2.2 Frozen-core orbitals
FROZEN,n 1 ,n 2 ,...,record.file;
n i is the number of frozen-core orbitals in irrep number i. These orbitals are doubly occupied in
all configurations and not optimized. Note that in earlier MOLPRO versions this directive was
called CORE and has now been renamed to avoid confusion with CORE orbitals in the MRCI
and CCSD programs.
record.file is the record name for frozen core orbitals; if not supplied, taken from orb on START
card. record.file can be specified in any field after the last nonzero n i . It should always be given
if the orbital guess is from a neighbouring geometry and should then specify the SCF orbitals
calculated at the present geometry. If a subsequent gradient calculation is performed with this
wavefunction, record.file is mandatory and must specify closed-shell SCF orbitals at the present
geometry. Note that record must be larger than 2000.
If the FROZEN card is omitted, then the numbers of core orbitals are taken from the most recent
MCSCF calculation, or otherwise no orbitals are frozen. If the FROZEN card is given as