Angular distributions of Ar reflected from molten metal surfaces

Recent experimental measurements of the angular distributions of monoenergetic beams of Ar atoms, with incident energies of up to 1 eV scattered from a molten In surface, are compared with calculated intensities. The data are described by classical scattering theory and the agreement indicates that the shapes of the lobes are dominated by single collisions with the surface, and the interaction potential has a smooth repulsive barrier similar to that commonly used to describe rare-gas scattering from crystalline metals. The attractive adsorption well of the interaction potential is considered, and is shown to have significant effects on the angular distributions at low incident energy. The dependence of the angular distributions on surface temperature is also well described. (C) 1999 American Institute of Physics. [S0021-9606(99)70124-8].