[molpro-user] CASPT2 - you should not be here error

[Brian Vest]

Dear Molpro Users:

I am trying to run a CASPT2 calculation on a linear molecule.  The
CASSCF calculation was good, but when the program came to the RS2C
portion, it crashed with this error:

1PROGRAM * RS2C (Multireference RS Perturbation Theory)     Authors:
H.-J. Werner (1993), P. Celani (1998)


 Convergence thresholds:  THRVAR = 1.00D-06  THRDEN = 1.00D-06

 Number of optimized states:  1  Roots:   1
 Number of reference states:  1  Roots:   1

 Reference symmetry:               1   Quintet
 Maximum shell in reference space  1
 Maximum shell inside CICON        4

 Maximum number of shells reduced from  4 to  2
 Maximum number of spin couplings:      5

 Reference space:       63 conf       63 CSFs
 N elec internal:      495 conf      495 CSFs
 N-1 el internal:      220 conf      220 CSFs
 N-2 el internal:       66 conf       66 CSFs

 Number of electrons in valence space:                     20
 Maximum number of open shell orbitals in reference space:  4
 Maximum number of open shell orbitals in internal spaces:  6


 Number of core orbitals:           6 (   2   1   1   0   2   0   0 )
 Number of closed-shell orbitals:   8 (   2   1   1   0   2   1   1 )
 Number of active  orbitals:       12 (   3   2   2   1   2   1   1 )
 Number of external orbitals:      14 (   5   1   1   1   2   2   2 )

 Molecular orbitals read from record     2140.2  Type=MCSCF/NATURAL
(state 1.1)

 Coulomb and exchange operators available. No transformation done.

 Number of p-space configurations:   3
 Closed shell energy (with core excluded) is        -82.69909179

 Reference wavefunction optimized for reference space (refopt=1)

 State     Reference Energy
   1        -284.66683221

 Number of blocks in overlap matrix:    16   Smallest eigenvalue:
0.21D-06
 Number of N-2 electron functions:     241
 Number of N-1 electron functions:     220

 Number of internal configurations:                   63
 Number of singly external configurations:           364
 Number of doubly external configurations:          3074
 Total number of contracted configurations:         3501
 Total number of uncontracted configurations:       1185

 Weight factors for SA-density in H0:    1.000000

 FIMAX=  0.35D+00  FXMAX=  0.91D-11  DIAG=  F  T  NOREF=1  NOINT=0
IHPPD=2

 Nuclear energy:                      84.14479224
 Core energy:                       -279.45437396
 Zeroth-order valence energy:        -13.29750183
 Zeroth-order total energy:         -208.60708355
 First-order energy:                 -76.05974866
 You should not be here!!

 ERROR EXIT
 CURRENT STACK:      CIPRO  MAIN

I did other calculations with different active spaces and different
states, and they all came to the same error.  However, I tried turning
off symmetry and it worked fine.  What's going on?

Cheers,
Brian