The vibrational multi-reference CI program requests a preceding VMCSCF calculation and accounts for
correlation effects on top of those considered in the VMCSCF run. Note, in all VMRCI calculations, configurations being
considered within the active space of the underlying VMCSCF calculation, will be relaxed. Configurations to be generated
for the VMRCI correlation space refer to all reference configurations and thus the VMRCI correlation space increases significantly
faster than the VCI space. Once parameters have been altered with respect to the defaults in the VMCSCF program, e.g. NGRID,
the same settings must be used within the VMRCI program. Further details are described in:
F. Pfeiffer, G. Rauhut, Multi-reference vibration correlation methods, J. Chem. Phys. 140, 064110 (2014).