Scattering of K and Cs by Several Compounds

Abstract

The nonreactive scattering of K from C10H16, (CH3)3CBr, SiCl4, Cl2, Br2, I2, ICl, (CN)2 C=C(CN)2, and Cs from HBr has been studied in experiments with crossed molecular beams. The primary alkali metal beam was velocity selected, and the scattered alkali metal was measured as a function of laboratory angle at a number of initial relative kinetic energies. Potential parameters are calculated from the rainbow scattering for K+C10H16, (CH3)3CBr, SiCl4, and Cs+HBr and also from the supernumerary rainbows for K+C10H16 and CH3)3CBr. An optical model analysis on K+(CH3)3CBr and Cs+HBr yields information about threshold conditions for reaction, probability of reaction, and total reaction cross section as a function of relative energy. For systems without rainbow scattering [K+halogens, (CN)2C=C(CN)2] an optical analysis made with a simple form for the absorption function requires a gradual change from a van der Waals potential at very large distances of separation of reactants to a more attractive potential at smaller distances. This indicates a gradual electron transfer on approach of reactants rather than an abrupt electron jump.