The evaluation of microcanonical and canonical rate constants using the stabilization theory of dynamics

Abstract

A new conceptually simple and computationally economic method of evaluating the spectral density is presented. The spectral density is then used to compute the microcanonical rate constant by a procedure that uses only the eigenfunctions and real eigenvalues of the system in a series of finite enclosures. Absorbing potentials or dilatation analytic methods are not needed. Thermal rates at low temperatures are obtained to high accuracy using very small basis sets. Examples are presented for single symmetric and asymmetric barriers fit to the potential for H+H2→H2+H and Cl+H2→HCl+H 1D reactions. An asymmetric double barrier is also studied so as to include a problem where narrow resonances contribute to the low temperature thermal rate constant. The method presented here should also be of great use in modeling electronic mesoscopic devices.