Xafs Spectroscopy and Glass Structure

This chapter provides a brief description of X-ray absorption fine structure spectroscopy (XAFS) theory and analysis methods, with particular attention to glasses. Examples of state-of-the-art studies in different glassy systems are presented along with a critical assessment of XAFS potential for such systems. The chapter commences with a note on the origins of x-ray absorption spectra. It illustrates a schematic typical experimental set-up for XAFS measurements. After discussing the physical mechanism of XAFS, it moves to EXAFS signals. For extracting the XAFS spectrum from the absorption coefficient, several operations have to be performed. Generally they are corrections for instrumental errors; pre-edge background subtraction; normalization; Fourier filtering, and the fitting procedure. This chapter reports two XAFS investigations on dopants in glasses: silver nanoparticles embedded in soda-lime glasses and Erbium doping in silica-based host matrices. It also outlines EXAFS accuracy and limitations and the XANES region.