Two hard sphere models for the reaction A+BC

Publisher Website
Google Scholar
Abstract
In an attempt to understand the mechanism of chemical reactions such as A+BC→AB+C or AC+B, we have constructed two models based upon the assumption that A, B, and C are hard spheres with B and C initially touching. Both models include an accurate estimate of the total cross section for A+BC collisions, the proper angular dependence of the activation energy, and a set of reasonable procedures for selecting the product state (AB+C, AC+B, A+BC, or A+B+C) once the final velocities of the three atoms have been computed. The two models differ in that one uses the sequential impulse model to calculate the final velocities, whereas the other uses the direct interaction with product repulsion (DIPR) model to obtain the velocities. The two models are used to study the O(3P)+H2 system, and the results are compared with quasiclassical trajectory (QCT) calculations on this system. At high energies the DIPR model appears to give better overall agreement with the QCT results. In particular, the QCT calculations show that at high energy the major product channel is the knockout reaction, where the O atom first hits one H atom but then goes on to react with the other atom. This effect is predicted by the DIPR model, but not by the sequential impulse model.