A GEOMETRIC MODEL FOR THE REGULAR DYNAMICAL BEHAVIOR OF COLLINEAR 3-ATOM REACTIONS INVOLVING AN INTERMEDIATE WELL

We propose a simple model which reproduces the regular classical dynamics of collinear three-atom reactions involving an intermediate well. The model is based on hard sphere scattering: the potential well is represented by a single wall which reflects the trajectories assumed to be straight lines. The position of the wall is related to the shape of the potential energy well in a simple way. The model yields results in good agreement with those obtained by quasi-classical trajectory calculations on several potential energy surfaces with different wells. This demonstrates that, in the case of the generic type of potential energy surface considered here, the distribution of energy among the products of the reaction is determined by simple geometric characteristics of the potential well.