Internal Energy of Reaction Products by Velocity Analysis. III. Center-of-Mass Angular Distribution and Product Excitation Function for K+Br2

A computer analysis of the product (KBr) velocity distribution experiments previously reported for the crossed molecular beam reaction K+Br2 is presented. The shape of the angular distribution of KBr in the center-of-mass (c.m.) system and the product internal energy (excitation) distribution function are evaluated, subject to the assumption of no coupling between the two distributions. In agreement with the conclusions of Herschbach, Datz, and their co-workers, the differential reaction cross section in the c.m. system is strongly forward peaked, characteristic of a ``stripping'' reaction. The maximum in the internal excitation function occurs near 100% of the total available energy. The results are in fair accord with the predictions of Karplus, Polanyi, and their co-workers, based on Monte Carlo trajectory analyses employing semiempirical potential surfaces.