RASCI calcualtion will crash with large active space, is it possible to solve?

Questions
#1

The error message shows as following,

 ##========================================##
 ||                                        ||
 ||              R A S M A N 2             ||
 ||________________________________________||
 ||                                        ||
 ||  Author:                               ||
 ||                                        ||
 ||        David Casanova (2010)           ||
 ||                                        ||
 ##========================================##
  • RAS-CI Dimensions: *
  •                                             *
  • Active Elec.: 10 ( 5, 5) Active Orb.: 9 *
  • Doubly Occ. : 216 Doubly Vir.: 853 *
  • Frozen Occ. : 0 Frozen Vir.: 0 *
  •                                             *
  • Total CI configurations: 31672620 *
  • Active configurations: 15876 *
  •  Hole configurations:   4572288             *
  • Particle configurations: 27084456 *
  •                                             *
  • Requested states: 20 *
  • Spin multiplicity: Singlets *
  •                                             *

Max. subspace vectors = 8000
Dim. of subspace vectors = 31672620
Room left in mega-array = 1023875000

Q-Chem warning in module rasman2/ras_dim.C, line 319:

Static memory may be insufficient to store the subspace vectors

Direct CI diagonalization

Iter Rts Conv Rts Left Ttl Dev Max Dev

Q-Chem fatal error occurred in module libmdc/newfileman.C, line 384:

FileMan error: End of file reached prematurely reading (132945008) bytes in file FILE_RAS_TMP_SS
Path: /scratch/csyang/qchem/qchem3733486/707.1

Please submit a crash report at Q-Chem Crash Reporter

==================================================================
Do you have any idea for solving the problem.
Also memory usage in input is that:
mem_total 160000
mem_static 64000

Thanks for your help.

#2

There’s a hard limit on MEM_STATIC (around 8000, I think - should be printed towards top of Q-Chem output file). I did not know that this version of RAS-CI uses static memory, if so this may indeed be a limitation. Please note there are two versions of RAS in Q-Chem, as described in the manual. One of them definitely avoid static memory, so I would try that one instead.