Anomalies in inelastic collision of methane molecular beam scattered from a Pt(111) surface

Molecular beam scattering from a Pt(111) surface has been performed using m ethane molecules with a kinetic energy ranging from 190 to 570 meV, and the results obtained are compared with the classical Hard cube model (HCM). Go od qualitative agreement is obtained as far as the dependence of the angula r distribution of reflected molecules on both surface temperature and beam energy is concerned. Anomalous behavior of experimental data is understood in terms of the modification of the surface by adsorption of methane interm ediate methyl fragments or more likely ethylidyne found by collision-induce d dissociation of methane molecules. He atom scattering (HAS) analysis is a pplied to monitor the corrugation in a potential energy surface which is mo dified by adsorption of foreign species. (C) 1999 Elsevier Science B.V. All rights reserved.