Determination of Electronic and Atomic Structural Parameters during Fast Ion Transport

摘要

X-ray absorption spectroscopy was used to determine the valence state and local structure in a vanadium bronze and a tungsten bronze series of fast ion conducting materials. The structure parameters confirm previous x-ray diffraction results; however, the direct determination of valence state(s) is a unique result. X-ray methods appear to offer real advantages for in situ characterization. X-ray absorption spectroscopy is able to single out each different kind of element in a complex material because the core-level absorption edges are well separated in energy. The region near the absorption edge, x-ray absorption near edge structure (XANES) contains information on the valence state and local symmetry of the absorbing atom. The extended x-ray absorption fine structure (EXAFS) above the absorption edge is caused by scattering of the ejected photoelectron and may be used to determine near neighbor structural parameters.