Abstract

X-ray absorption fine structure (XAFS) spectroscopy is a local structural technique that recently celebrated its 50th anniversary. Its two parts, X-ray absorption near edge structure (XANES) and extended XAFS (EXAFS), found their applications for many problems in basic and applied research, spanning most, if not all, scientific fields. As the name of the technique says, it requires X-rays, they get absorbed by the material of and the absorption coefficient as a function of energy exhibits fine structure that is the focus of the analysis. In my talk I will overview the basic principles of XAFS, the information about the local structure, electronic properties and dynamics it contains, and how to extract it from the data. I will discuss the nearsightedness of XAFS, its elemental specificity, and the reason why the data can be represented as a collection of “snapshots”, capturing not only average, but also the details of the distribution of local structure around the average. Drawing from many case studies in chemistry, physics, materials science and engineering, environmental science, structural biology and other fields using XAFS, I will overview its strengths, limitations, and recent strategies developed in the last decade to further improve the technique.