Extended energy loss fine structure technique: an analytical tool for surface and bulk characterization

The determination of surface atomic arrangements is still a difficult task because most uhv techniques are not capable of providing direct information on the atomic geometry of the surface unit cell. Moreover, a full structural determination requires complex electron scattering models or analysis of photoexcited electron spectra all of which rely on crystal potentials and atomic interactions which are not precisely known. Thus, it is necessary to develop a structural probe which combines the use of a simple experimental apparatus with a straightforward method to extract the local order information around the investigated atom. All these requirements hold for the EELFS (Extended Energy Loss Fine Structure) spectroscopy that measures the fine structures which extend for a few hundred electron volts above the ionization edges of a surface atom. In this paper we review some recent applications of the EELFS technique to give local structural parameters.