X-RAY-ABSORPTION SPECTROSCOPY APPLIED TO SURFACE-STRUCTURE - SEXAFS AND NEXAFS

The application of both surface extended X-ray absorption fine structure (SEXAFS) for determining adatom-substrate distances and adsorption sites, and near-edge X-ray absorption fine structure (NEXAFS) for determining adsorbed molecular orientations and bonding changes, is simple, direct, and now routine. The events leading up to developing these methods, however, were neither simple nor direct, and by no means were they routine. Communities of X-ray spectroscopists, synchrotron radiation researchers, and surface scientists overlapped to create a-particularly special and fertile environment. This article presents a brief overview of these scientific and sociological events from a personal perspective, with emphasis on some of the earlier history not familiar to many surface science practitioners. Comments about the capabilities, limitations, and accomplishments of SEXAFS and NEXAFS are also mentioned.