Sensitivity analysis of the potential for elastic gas-solid scattering from surface defects

The role of surface defects in elastic gas-solid collisions is investigated by means of a recently developed numerical procedure based on the Møller operator and wavepackets. Since the procedure explicitly evaluates the scattering wavefunction, it yields the probabilities for scattering from the given initial state into all possible final states as well as the sensitivity of the probabilities with respect to variations in the gas-surface potential. Probabilities and their functional sensitivities are calculated for a simulated Pt surface exhibiting various configurations of vacancies: isolated sites, "interacting" di-vacancies and closely-packed tri-vacancies. The functional sensitivities indicate which regions of the gas-defect-solid potential are most relevant to the scattering dynamics. The resultant physical insight should be ultimately helpful for inverting experimental data to obtain the interaction potential.