RECENT PROGRESS IN SURFACE-ANALYSIS

The most basic requirements in surface analysis are to identity the chemical constituents and to determine their structural arrangement. Progress in chemical analysis has been rapid since the introduction of Auger electron spcctroscopy, but the extreme complexity of low energy electron diffraction analysis has limited surface crystallography to a few relatively simple structures. It may, however, be possible to extract structural information, even from relatively disordered surfaces, using extended fine structure techniques. Fine structure variations have been observed to extend hundreds of electron volts above appearance potential thresholds. This structure is analogous to extended X-ray absorption fine structure (EXAFS), and can be interpreted in terms of interatomic distances in the surface region. The recent development of extended appearance potential fine structure (EAPFS) analysis is reviewed. The technique is of potential benefit in the resolution of LEED analysis problems on single crystal surfaces, as well as in the study of less ideal surfaces. The present limitations of the technique are stressed and analytical and experimental approaches to minimizing these limitations are discussed. © 1979.