The MgO (001) surface studied by time‐resolved He atom scattering

Abstract

The vacuum‐cleaved MgO (001) surface is studied by angle and time‐resolved scattering of 17.4 meV He atoms. The angular distributions of elastic diffuse and inelastic scattering show several clear, sharp structures, which are identified with particular selective adsorption resonances with the incident beam or with inelastic final states. Of the two principal azimuths, the in‐plane diffuse elastic scattering is greater along 〈100〉, consistent with a preferred step orientation along and perpendicular to this direction. The time‐of‐flight spectra show many well‐resolved peaks which yield the dispersion of the surface Rayleigh mode over 90% of the Γ̄X̄ and Γ̄M̄ directions. These results agree with a shell model calculation employing bulk parameters.