The Location and Characterization of Stationary Points on Molecular Potential Energy Surfaces

Abstract

A procedure is described for the location of stationary points on potential energy surfaces from computed values of the energy and (if available) energy derivatives. The procedure is based on least-squares fitting of the available data by a polynomial in a nonredundant subset of the Cartesian coordinates of the atoms, followed by location of an appropriate stationary point of the polynomial. This process is iterated with the addition of new data points. Also discussed are the calculation of vibrational frequencies and the location of reaction paths. An application to the CH 5 + ion is described.