It is advisable to restore the wavefunction definitions using VBDUMP cards here and in the CASSCF calculation (see Section 16.8.6). The default record name (vbdump) is 4299.2. If a VBDUMP card is not present and record 4299.2 does not exist, then CASVB will attempt to generate the wavefunction information automatically based on the latest MCSCF calculation (however, STATE and WEIGHT information will not be restored in such a case).
If present, the VBDUMP card must occur first in the CASVB input. It is not required for variational calculations.
Note that in the majority of cases (e.g., if a CASVB
run occurs immediately after MULTI, or for variational calculations),
explicit specification of dump records with vbdump is not required.