On the low energy limit of reflection and sticking coefficients in atom surface scattering. I. Short range forces

Abstract

The elastic scattering of atoms and molecules by solid surfaces is treated in a nonperturbative way using the single particle Green's function of the scattered particles. For sufficiently short ranged interactions the elastic reflection coefficient is found to approach unity in the limit of zero energy of the incident particles. Unitarity then implies zero total reaction coefficient including the sticking coefficient. The findings of the first order distorted wave Born approximation are thus generalized. The result is not in contradiction to the experimental observation of sticking coefficients increasing with decreasing energy, since quantitative approximate calculations show that the limit is reached only at extremely low energies.