A quantitative analysis of the factors controlling the inversion barriers in AH 3 molecules

Abstract

The importance of the energy effects associated with the HOMO-LUMO interaction in a series of AH 3 molecules has been investigated quantitatively in the framework of ab initio SCF-MO computations in terms of total energies and in terms of a PMO approach. The computations have been performed at the STO-3G and 4-31G levels, with the addition of s, p diffuse and d polarization functions and the effects associated with the various types of function have been discussed. In all cases, potential energy curves with and without the various types of energy effects have been constructed. A theoretical model which rationalizes the trend of the inversion barriers in the AH 3 molecules has been derived, consistent with the results obtained using an STO-3G basis set plus diffuse functions. This computational level seems, in fact, to provide accurate values of the inversion barriers.