Surface structure determination using x-ray standing waves

The technique of x-ray standing waves as a means of structure determination is reviewed with special emphasis on its application to the investigation of adsorbed atoms and molecules at well-characterized single crystal surfaces in ultra-high vacuum. Topics covered include: the physical principles of the method and the underlying theory; methods of detection of the x-ray absorption and their relative merits; the specific advantages of photoelectron detection together with a description of the modified method of data analysis and its underlying physical basis (required to account for non-dipolar angular effects in the photoemission process); some practical issues of data analysis and interpretation including recent developments in the use of structural 'imaging' by direct inversion of the measured structural parameters. A broad survey of applications is included covering atomic and molecular adsorbates on semiconductors and metals as well as the use of the technique to obtain site-specific electronic structure information. Some comments on likely future developments and applications are given.