Rare gas scattering from molten metals examined with classical scattering theory

Classical limit expressions of the differential reflection coefficient for atoms scattering from a surface are compared with recent experiments for the scattering of monoenergetic beams of Ne, Ar, and Xe with incident energies in the eV range from the molten metal surfaces Ga, In, and Bi. We find that single collision events usually make the greatest contribution to the backscattered intensity, double collision events make a significant but smaller contribution, and scattering of atoms that are completely trapped and subsequently thermally desorbed has a small probability. In the case of large mass incident projectiles and small mass target atoms we find some evidence for collective mass effects of the target. An analysis of the temperature dependence of the intensities shows that these surfaces act neither as a smooth continuous repulsive barrier nor as a collection of discrete scattering centers; rather they exhibit a behavior in between these two extremes. (C) 1997 American Institute of Physics.