Interaction between surface phonons and bond vibrations of molecules adsorbed perpendicular to a solid surface

Abstract

The interactions between bond vibrations of molecules adsorbed perpendicular to an adsorbent surface and surface vibrations of the solid are described. A method based on the generalized Langevin equation formalism is extended to adsorption systems with this geometry. Equations for the spectral density of the autocorrelation function of the molecule bond deviation and the adsorption bond deviation are derived. A self-consistent solution of these equations for a formamide molecule adsorbed via the nitrogen atom on an Ni(111) surface shows different behaviour from the case of a molecule adsorbed parallel to the surface. The effect of the phonon-vibration interactions on the rate constant for bond dissociation of the adsorbed molecule is estimated.