MOLPRO

20 THE CI PROGRAM 152
refstat:
mxshrf :
Specifies from which state vector the configurations are selected.
This only applies to the case that the configurations
were saved in a state-averaged calculation. If refstat is zero or
not specified, the configurations are selected from all states. If
refstat is greater than zero, then the specified reference state is
used. If refstat is less than zero, then all appropriate reference
states are used. Lastly, if refstat is of the form istat1.istat2,
states istat1 through istat2 are used.
maximum number of open shells in the selected or generated
configurations.
20.2.8 Occupation restrictions
RESTRICT,nmin,nmax,orb 1 ,orb 2 ,...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 ,
..., 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.
20.2.9 Explicitly specifying reference configurations
CON,n 1 ,n 2 ,n 3 ,n 4 ,...
Specifies an orbital configuration to be included in the reference function. n 1 , n 2 etc. are the
occupation numbers of the active orbitals (0,1,or 2). Any number of CON cards may follow each
other, but they must all appear directly after a SELECT card.
20.2.10 Defining state numbers
STATE,nstate,nroot(1),nroot(2),...,nroot(nstate);
nstate is the number of states treated simultaneously; nroot(i) are the root numbers to be calculated.
These apply to the order of the states in the initial internal CI. If not specified, nroot(i)=i.
Note that it is possible to leave out states, i.e.,
STATE,1,2;
STATE,2,1,3;
! calculates second state
! calculates first and third state