Quasi-ab initio dynamics: a test trajectory study of the reaction using energies and gradients based on scaling of the external correlation

Abstract

We have carried out a test dynamics study of the prototype exchange reaction by running quasi-classical trajectories [`]on-the-fly' using ab initio correlated energies which have been previously corrected semiempirically by the double many-body expansion plus scaling of the external correlation method to account for size-limitations of the one-electron basis set and configuration interaction expansion. The method is general and gives results in agreement with conventional trajectory calculations carried out on the accurate double many-body expansion potential energy surface for .