Reflection XAFS

Abstract

“Reflection XAFS” or “ReflEXAFS” is a particular collection mode of X-ray Absorption Spectroscopy (XAS) data with the probe beam impinging on the sample in total external reflection conditions. The main advantage of total reflection XAS is that the extinction length of the probe beam is greatly reduced respect to the normal incidence. This makes ReflEXAFS a surface-sensitive technique in the range of a few nm with the considerable advantage that it does not need Ultra High Vacuum conditions like electron-based techniques. Then, this method can be applied to a variety of interfaces (gas-solid, liquid-solid, liquid-liquid and solid-solid) realizing ‘in operando’ conditions for the materials under study. In this contribution the basic theoretical aspects of this technique are reviewed and then a list of remarkable experimental apparata is presented. Successively, some examples of experiments using Total Reflection XAS are described and in the final section some perspectives of development of this technique are given.