$GCILST

$GCILST group (required for SCFTYP=MCSCF if CISTEP=GENCI) (required if CITYP=GENCI)
This group defines space products to be used in the general CI calculation, or in a MCSCF wavefunction. The input is free format.
Line 1: NSPACE ISYM
The first line gives the total number of space products to be entered in the second lines.
The option ISYM can be omitted, or given as 0, in which case the program will verify that all space products typed in the second lines indeed have the spatial symmetry defined by ISTSYM in the $GEN or $CIGEN input groups. If ISYM is 1, the user is indicating that more than one space symmetry is known to be in the list, that this is intentional, and the program should proceed with the calculation. This might be of use in state averaging two representations in a group that has more than two total representations, and therefore faster than turning symmetry off completely by GROUP=C1. ISYM=2 has the same meaning but turns on additional printing.
Line 2 is repeated NSPACE times. Each line 2 contains NACT integers, which must be 0, 1, or 2, and therefore tells the occupation of each of the active orbitals in each space product. An example input is:
 $GEN GLIST=INPUT NELS=6 NACT=4 SZ=0.0 $END
 $GCILST
5
2 2 2 0
2 1 2 1
2 0 2 2
2 2 0 2
0 2 2 2
 $END
which generates 6 Ms=0 determinants, much less than the 16 determinants in a C1 symmetry full list for 6 e- in 4 MOs.
The second space product above generates two determinants. All space products with singly occupied orbitals are used to form all possible determinants, to ensure that the final states are eigenfunctions of the S**2 operator (meaning they will be pure spin states).
Note that there is no way at present to generate lists such as singles and doubles from a single reference.
Convergence of MCSCF calculations will depend on how well chosen your determinant list is, and may very well require the use of the JACOBI or FULLNR convergers.