54.2.1 Explicit definition of active spaces


Within the VMCSCF program the active space can be specified in a general manner (keword NACT), which means that the same number of active modals for each mode will be used. Alternatively, one may use the NACT directive. This allows to specify active spaces for the individual modes. Typically such definition refer to just one vibrational state and thus the program should be used within the USERMODE mode.

The number of active modals for mode n is set to m. This always includes the vibrational ground state. In order to resolve Fermi resonances, one would need to choose m at least to be 3, which corresponds to the modals 0, 1 and 2.

molpro@molpro.net 2018-12-13