Translational energy requirements and disposal in molecular collisions. II. Branching ratios and products state distributions for the exchange reactions of alkali atoms with alkali halides

Experimental reactive/non-reactive branching ratios in the complex forming M' + MX collisions are often found to deviate from those computed by statistical theories. Information theory, using the momentum transfer constraint, is employed to relate this deviance to the distribution of translational energy in the products. The experimental results for the branching ratios and mean product energies in K + CsF and K + RbF (obtained by Stolte, Proctor, and Bernstein) are found to be consistent and are used to predict the translational energy distribution in the products. The low branching ratio in K + CsF is shown to imply that the energy distribution for non-reactive scattering is nearly statistical while for reactive scattering the distribution is significantly narrower compared to the statistical results. Using the experimental results for K + CsF and K + RbF it was also found possible to predict the branching ratio and the energy disposal in the Cs + KF and the Rb + KT reactions. The experimental results for the mean product energies in M + M'X reactions. X = Cl or I (obtained by Miller, Safron, and Herschbach), are used to compute the branching ratios in good agreement with the experimental values. A relation between energy disposal and the geometrical structure of the collision complex is discussed as a possible dynamical model for the proposed connection between branching and products energy distribution in complex forming reactions.