Sensitivity of elastic gas-surface scattering to the potential: A functional sensitivity approach based on wave packet dynamics

Functional sensitivity analysis is used to study the effect of potential structure upon the elastic scattering of He atoms from a one-dimensional surface. The calculations are implemented by computing the total scattering wave functions from a wave packet calculation by a Møller wave operator method. The functional sensitivities of the various diffraction probabilities for several angles of incidence and surface corrugation are studied. The method is extended to examine the role of potential structure for a surface with adsorbed impurities. It was observed that the various diffraction processes draw from local regions of the potential in very different ways. At high angles of incidence for back scattering and particularly for strong surface corrugation, the large protruding portions of the surface cast a "shadow" of lower dynamical sensitivity. Results of this type should ultimately be insightful for the inversion of experimental data to obtain the interaction potential.