INELASTIC-SCATTERING FROM EINSTEIN MODES OF SURFACE-DEFECTS

We consider the theory of inelastic scattering of atoms by isolated surface defects which have nearly dispersionless vibrational modes. Explicit calculations are carried out corresponding to the cases of chemisorbed CO on a Pt(111) surface, or heavy rare gases physisorbed on Pt(111) or Ag(111) surfaces. The multiphonon intensities are compared with available data. We show that the multiphonon intensities measured as a function of scattering angle exhibit broad oscillations similar to those observed in elastic scattering, and the polarization of the Einstein mode has a large effect on the envelope of these oscillations. © 1990 The American Physical Society.