Selection rule in the vibrational–electron-hole pair energy transfer for molecules interacting with metal surfaces

Abstract

In the scattering of a polyatomic molecule from the surface of a metal, there can be exchange of energy between electron-hole pair excitations of the metal and vibrations of the molecule. A possible mechanism for this is electron transfer to an (affinity) orbital of the molecule. We point out that certain vibrations would be selectively excited/deexcited in this mechanism. A similar rule exists for the damping of vibrations of molecules adsorbed on metal surfaces.