Tests of collinear quasiclassical trajectory transmission coefficient correction to transition state theory

Abstract

We test the accuracy of a collinear quasiclassical trajectory transmission coefficient correction to conventional transition state theory. Comparisons are made between the so-modified transition state theory, conventional transition state theory, and previously reported three dimensional quasiclassical trajectory rate constants for several reactions. They are the O(3P)+H2(ν = 0), H2(ν = 1) reactions on three different potential energy surfaces, the F+H2(ν = 0) reaction on the LEPS surface of Muckerman (no. 5), and the H+H2(ν = 0) reaction on the Porter–Karplus surface. Although each of these systems has a collinear transition state, they span a wide variation in saddle point location and classical barrier height. We find that the collinear quasiclassical trajectory transmission coefficient very successfully corrects the conventional transition state rate constant even for the O(3P)+H2(ν = 1) reaction where the latter differs from the 3D quasiclassical one by two orders of magnitude.