$GCILST group      (required by 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 STSYM 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                                 
2 2 2 0                                                                         
2 1 2 1                                                                         
2 0 2 2                                                                         
2 2 0 2                                                                         
0 2 2 2                                                                         
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 with arbitrary lists of                       
space products will depend on how well chosen your list is,                     
and may very well require the use of FULLNR or JACOBI                           
A utility program to pre-select the important part of CI                        
expansions with high excitation levels, based on                                
information from CI-SDT calculations, is distributed with                       
the source code.  See the file                                                  
for more information.                                                           

generated on 7/7/2017