QUANTUM SCATTERING OF AN ATOM FROM AN ADSORBED MOLECULE ON A SMOOTH METAL SURFACE.

The scattering of He atom from a single CO molecule adsorbed on a smooth metal surface is modeled with an ab initio average potential of He-CO interaction super-imposed on a perfect reflecting flat surface. Integral as well as differential cross sections are obtained from exact quantum mechanical calculations. Rayleigh oscillations are shown to be present in the energy dependence of the integral cross sections. Among many Fraunhoffer and reflection-symmetry oscillations in the differential cross sections, a single peak is identified as the rainbow oscillation. This parameter free calculation can explain the observed integral and differential cross sections better than the previously used hard hemisphere model. [ABSTRACT FROM AUTHOR]