MOLPRO

19 THE MCSCF PROGRAM MULTI 131
FROZEN,record.file, then the orbitals corresponding to atomic inner shells are taken, i.e., 1s for
Li–Ne, 1s2s2p for Na–Ar, etc. A FROZEN card without any specification resets the number of
frozen core orbitals to zero.
19.2.3 Closed-shell orbitals
CLOSED,n 1 ,n 2 ,...,n 8
n i is the number of closed-shell orbitals in irrep number i, inclusive of any FROZEN orbitals.
These orbitals do not form part of the active space, i.e., they are doubly occupied in all CSFs.
In contrast to the core orbitals (see FROZEN), these orbitals are fully optimized.
If the CLOSED card is omitted, then the data defaults to that of the most recent MCSCF calculation,
or else the atomic inner shells as described above for FROZEN.
19.2.4 Freezing orbitals
FREEZE,orb.sym;
The specified orbital will not be optimized and will remain identical to the starting guess.
orb.sym should be an active or closed-shell orbital. If orb.sym is a frozen core orbital, this
card has no effect.
19.3 Defining the optimized states
Each state symmetry to be optimized is specified by one WF card, which may optionally be
followed by STATE, WEIGHT, RESTRICT, SELECT, CON, and/or PSPACE cards. All
cards belonging to a particular state symmetry as defined on the WF card must form a block
which comes directly after the WF card. The cards can be in any order, however.
19.3.1 Defining the state symmetry
The number of electrons and the total symmetry of the wavefunction are specified on the WF
card:
WF,elec,sym,spin
where
elec
sym
spin
is the number of electrons
is the number of the irreducible representation
defines the spin symmetry, spin= 2S (singlet=0, doublet=1, triplet=2,
etc.)
Note that these values take sensible defaults if any or all are not specified (see section 10.2).
The input directives STATE, WEIGHT, LQUANT, SELECT, PUNCSF always refer to the state
symmetry as defined on the previous WF card. If such a directive is found before a WF card has
been given, the current state symmetry is assumed, either from a previous calculation or from
variables [MC]SYMMETRY(1) and [MC]SPIN(1) (if these are defined). If any of these cards
or a WF card is given, the variables STATE, WEIGHT, LQUANT, SELECT are not used, and the
number of state symmetries defaults to one, regardless of how many symmetries are specified
in variable [MC]SYMMETRY.