MOLPRO

20 THE CI PROGRAM 151
WF,15,2,1; !define wavefunction symmetry (2)
REF,1; !define additional reference symmetry (1)
For linear geometries the same results can be obtained more cheaply using C 2v symmetry,
WF,15,2,1; !define wavefunction symmetry (2)
REF,1; !define additional reference symmetry (1)
REF,3; !define additional reference symmetry (3)
or
WF,15,3,1; !define wavefunction symmetry (2)
REF,1; !define additional reference symmetry (1)
REF,2; !define additional reference symmetry (2)
Each REF card may be followed by RESTRICT, SELECT, and CON cards, in the given order.
20.2.7 Selecting configurations
SELECT,ref1,ref2,refthr,refstat,mxshrf ;
This card is used to specify a reference configuration set other than a CAS, which is the default.
Configurations can be defined using CON cards, which must appear after the SELECT card.
Alternatively, if ref1 is an existing MOLPRO record name, the configurations are read in from
that record and may be selected according to a given threshold.
The select card should normally be placed directly after the WF or REF card(s), or, if present,
the RESTRICT cards. The general order of these cards is
WF (or REF)
RESTRICT (optional)
SELECT (optional)
CON (optional)
ref1=rec1.file:
ref2=rec2.file:
refthr:
(rec1>2000) The configurations are read in from the specified
record. See section 19.5.4 about how to save the configurations
in the MCSCF calculation. If ref1 is not specified, the program
assumes that the configurations are read from subsequent CON
cards (see CON).
(rec2>2000) additional configurations are read from the specified
record. If rec2 is negative, all records between rec1 and
abs(rec2) are read. All configurations found in this way are
merged.
Selection threshold for configurations read from disc (records
rec1–rec2). This applies to the norm of all CSFs for each orbital
configuration.