Heavy atom-surface scattering at hyperthermal energies

We have measured energy- and angle-resolved scattered spectra for 10-250 eV Rb+ ions incident on a Cu(001) surface at angles of 45 degrees and 65 degr ees with respect to the surface normal. These spectra indicate that the sca ttering for this heavy atom-surface system involves multiple collisions wit h surface atoms that are binary in nature. Using a classical trajectory sim ulation, the trajectories that lead to scattering are analyzed and are show n to be similar to results obtained in light atom-surface systems. Based on the simulation results, a new trajectory type is proposed that involves th e rehitting of a scattered Rb+ ion by a recoiling surface atom. (C) 2001 Pu blished by Elsevier Science B.V.