ELECTRON-MOLECULE SCATTERING AND PHOTODYNAMICS AT SURFACES

This article discusses the role of electron-molecule scattering in the photodynamics of adsorbed molecules. In comparison with gas phase photochemistry, adsorption on the surface opens up new channels for light absorption. Specifically, the interaction of electrons photoexcited in the substrate with the adsorbed molecule may lead to molecular dissociation and desorption as well as to chemical reactions between co-adsorbed molecules. As a consequence, the physics of the electron-molecule scattering event is a key element in the interpretation of the photodynamics. These issues are illustrated by a comparison of recent electron stimulated and photon stimulated desorption studies of a model system, physisorbed 02/graphite.