Chapter 72 - Structural dynamics and electronic structure changes probed with lasers and x-rays

Abstract

Over the past years, much effort has been invested to combine the ultrashort time resolution of lasers with the high atomic-scale resolution of structural techniques, such as electron diffraction, x-ray diffraction, and x-ray absorption spectroscopy (XAS). The latter is a mature technique to probe the electronic and structural properties of a large class of systems, ranging from solid-state materials to proteins. A variety of fine structure near the characteristic edge of a selected element delivers this information, the so-called X-ray absorption near edge structure (XANES), while at higher energies, it is the so-called Extended x-ray absorption fine structure (EXAFS). In many-body systems, these features are caused by the presence of adjacent atoms and their proper analysis delivers information about the local geometric structure to high accuracy. Research based on time-resolved XAS in an optical pump-x-ray probe scheme was first implemented at synchrotron radiation sources. This chapter allows evaluation of the feasibility of future time-resolved XAS experiments, which are presented together with the new results.