X‐Ray Absorption Fine Structure Spectroscopy

Abstract

This chapter provides the reader with an understanding of the physical bases, experimental considerations, and data analysis procedures of X-ray absorption fine structure (XAFS). Due to the high intensities of synchrotron x-ray sources, XAFS can be performed on soils, suspensions, and solutions without the need for sample alterations, i.e., in situ analysis. A unique feature of XAFS is that both detailed speciation information is provided in addition to accurate structural measurements. The pre-edge and, primarily, the x-ray absorption near edge structure regions of XAFS contain information on the electronic state of the absorbing element, its symmetry, and thus its local chemical environment. The extended x-ray absorption fine structure (EXAFS) can provide much information on the structure of soil constituents and on structural alteration induced by reactions. Numerous computer programs have been written for EXAFS analysis. Many of these are free to general users and can be accessed through public domain accounts.