Rainbows and Resonances in Molecule-Surface Scattering

Abstract

The effect of rotational rainbows in molecule-surface scattering is investigated for NO-Ag(111). It is demonstrated that recent experimental state distributions can be qualitatively repruduced with one potential energy surface without inclusion of the thermal motion of the surface atoms. We conclude that the interaction potential should be quite asymmetric, i.e., the interaction of N and 0 with the metal surface should be different. The mean rotational energy transfer in-creases linearly with the collision energy and the surface temperature which is in accordance with experimental findings. The second topic deals with selective adsorption resonances in H2 (and isotope variations)-metal surface scattering. The effect of rotationally mediated selective adsorption for HD as impinging molecule and its dependence on the potential energy surface is discussed. A quantitative prediction of the potential anisotropy is made for H2-Ag (110) using the experimentally observed magnetic sublevel splitting of selective adsorption resonances. It agrees very well with a recent estimation based on ab initio methods.