Self-consistent field investigation of vibrations of atomic adsorbates

The vibrational self-consistent field method is presented and applied to a study of the coupling between an atomic adsorbate and a corrugated surface. A dispersion in the adsorbate vibrational energies results from this coupling and for an infrared transition this dispersion results in a linewidth in an IR spectrum. A model calculation considering a linear corrugated surface and parameters for H–LiF (001) yields a maximum dispersion of between 1 and 6 cm−1 depending on the surface state, with the largest dispersion occurring for surface states with energies which are roughly equal to the barrier height separating adsorbate binding sites.