Electronic excitation in atomic adsorption on metals: A comparison of ab initio and model calculations

Results of calculations using time-dependent density functional theory and an analytic solution of the mean-field Newns-Anderson model are compared for the spectrum of electronic excitations generated by the adsorption of H-atoms on the Al(1 1 1) surface. It is shown that the main features of the spectra as a function of the incident energy of the H atoms are similar, but some details are not in quantitative agreement.