The adsorption site of the surface formate species chemisorbed on Ni{110}

The selection rules pertinent to the dipole scattering of electrons involved in the vibrational excitation of surfaces are exploited to provide information on the nature of the adsorption site occupied by the surface formate species chemisorbed on a Ni{110} single crystal surface. In particular, attention is concentrated on the observation, in specular scattering geometry, of a surface phonon mode which has its origin at the S̄ point of the clean surface Brillouin zone, and clearly indicates that short bridge sites are occupied.