Dynamical polarization effects in dissociative sticking of a diatomic molecule with energy loss to the substrate

We solve exactly and fully quantum mechanically a model Hamiltonian which describes energy loss to the substrate in dissociative sticking. The inelastic process is assumed as being due to electron-hole pairs. Results are calculated for the system H-2/Cu(111). It is shown that the main effect is a dynamical polarization of the electron system with no electron-hole pairs in the final channel, which enhances the sticking coefficient with respect to that calculated only with the elastic molecule-solid potential. Substrate excitations in the final channel contribute little to the sticking coefficient.