Theoretical Considerations on Surface Extended X-Ray Absorption Fine Structure (EXAFS)

We have investigated the following theoretical points relevant to surface EXAFS: proportionality of the signal to the absorption cross section, analysis of the oscillations with the simple EXAFS formula, accuracy in the determination of distances and coordination numbers, transferability of phase shifts and amplitude factors. We describe some of the most used techniques to record the Surface Extended X-Ray Absorption Fine Structure (SEXAFS) oscillations, both the photon induced techniques and the electron induced ones, such as the Auger effect, the total or partial yield, the ion desorption technique, the appearance potential spectroscopy and surface reflection electron loss spectroscopy; and in each case we underline their potentialities and their limitations