A review of auger photoelectron coincidence spectroscopy

The application of coincidence detection techniques produces a dramatic increase in the information obtained from particle and photon scattering studies. A clear illustration of this is given by Auger Photoelectron Coincidence Spectroscopy (APECS). By coincident detection of the ejected photoelectron and the resulting Auger electron during x-ray excited Auger spectroscopy, it is possible to distinguish the true origin of peaks and satellites within the Auger spectra. For example, it becomes possible to separate standard Auger processes from those occurring in conjunction with Coster-Kronig transitions and from those either followed or preceded by shake-off or shake-up transitions. In addition, the technique often allows the separation of overlapping series of Auger peaks, thus permitting the study of individual elements within compounds and alloys. These possibilities will be illustrated primarily by reference to APECS studies of 3d transition metal elements.