AN EXTENSION OF AB-INITIO MOLECULAR-ORBITAL THEORY TO NUCLEAR MOTION

We propose an extension of the quantum chemical molecular orbital (MO) method to describe the nuclear motion. Both electronic and nuclear wa vefunctions are simultaneously solved with the full variational MO met hod, by which exponents and centers of gaussian-type function (GTF) ba sis sets are optimized as well as the linear combination of GTF coeffi cients. Applications of the method to [F-;e(+)], FH and FD systems are carried out. The calculated bond lengths and harmonic frequencies agr ee well with the experimental values. (C) 1998 EIsevid Science B.V. Al l rights reserved.