Influence of internal rotation on exothermic reactions between neutral molecules at low temperatures.
A Langevin-type transition state model is developed to take account of the internal rotation energy in exothermic reactive collisions between neutral molecules. Energy and total angular momentum are both rigorously conserved. Reactive rate coefficients attain a maximum of a few 10(-10) cm(3)/s at temperatures in the range 10-30 K decreasing rapidly at higher temperatures. Results for a representative selection of well-studied systems, Si-O(2), CN-O(2), Si-NO, are in good agreement with experimental observations. At higher temperatures, typically around 100 K or greater, the rate coefficient exhibits a T(-1/3) dependence.
McCarroll
Ronald
R
Laboratoire de Chimie Physique-Matière et Rayonnement, UMR 7614 du CNRS, Université Pierre et Marie Curie, 75231-Paris Cedex 05, France. ronald.mac_carroll@upmc.fr