NEW VIBRATIONAL SELF-CONSISTENT-FIELD PROGRAM FOR LARGE MOLECULES

A recently developed, general computer program that performs vibration al self-consistent field (VSCF) calculations for large molecules is de scribed. The program, which we refer to as VSCF_95, requires as its on ly input a force field in mass-scaled normal coordinates. Currently, i t is limited to a maximum of 200 normal modes, and the force field is limited to coupling terms involving a maximum of six normal modes, wit h a maximum order of six in any normal mode. As output the program ret urns VSCF energies for specified quantum states. We illustrate the cod e with two new applications. The first is to HCO, for which we use a f ull sixth-order force field. The second is to a model of the fullerene , C-60 for which we have calculated a 75,731-term force field, which i ncludes all anharmonic terms up to fifth order, and all two-mode coupl ing terms up to fourth order. (C) 1996 by John Wiley & Sons, Inc.