Auger lineshape analysis of molecules and solids

Considerable recent theoretical work has shown that core--valence--valence Auger lineshape analysis may often be successfully made in terms of the molecular orbital structure of the molecule or the band structure of the solid. This approach assumes a priori that the final state hole motion is uncorrelated. Limitations to this approach include the highly correlated final states observed in ionic and narrow band solids (as Cu). Complications to this approach include the initial state valence screening of the core hole which affects the Auger decay probabilities. However, much useful information about the local density of states (local chemical environment) may be extracted in covalent and metallic materials. Examples from molecular (CH4, C2H4, C2H6, and C3H8) and solid state (Cu and Be) spectra are presented and the state of our understanding of lineshape analysis is summarized