Atomic and electronic structure of surfaces studied with synchrotron radiation

Many synchrotron radiation techniques developed in the past decade use the photoemission process to study surfaces and, in particular, adsorbates. Most of these probe the local surface electronic states. Recently, some photo− emission techniques have evolved into probes of the surface atomic structure as well. These structure−sensitive techniques are photon−polarization− dependent photoemission, adsorbate band structure mapping, surface−EXAFS, and photoelectron diffraction. In this article synchrotron experiments in both categories are discussed, and representative results are given which illus− trate their applications to surface structural problems of fundamemtal interest. We discuss in particular the distinctive advantages of these new surface− sensitive structural probes with respect to other more established techniques.