On the interpretation of differential scattering in rare gas excitation transfer systems: He* (2 1S)+Ne and Ar* (4s 3P2/sub ,/0)+Kr, Xe

Crossed beam time-of-flight measurements on scattered excited species in the title systems are used to identify some of the unusual structure at wide scattering angles as being due to reactively scattered excited products, and to correct two previous misinterpretations. Unexplained structure remains in the elastic scattering, while the reaction products are scattered sharply forward in every case, giving rise to resolved wide-angle peaks corresponding to each state or group of states of the excited atom product. The time-of-flight diagnostic thus enables ''reactive scattering spectroscopy'' for these and other systems, in which absolute state-to-state reaction cross sections, branching ratios, and reaction thresholds may be obtained from analysis of the angular distribution