Energy of Auger Peaks

The energy of an Auger transition, for example KLM, is to a first approximation given by  

Ek is the binding energy of an electron in the K-shell, etc. rp is the work function  

The SE term accounts for the relaxation effects involved in the decay process, which leads to a final state consisting of a heavily excited, doubly ionized atom. 

Auger energies are as element-specific as binding energies in XPS. However, chemical information such as oxidation states is much more difficult to abstract. 

In general, XPS is the preferred technique for studying oxidation states and ligand effects. However, there is a good reason why one should be interested in deriving chemical information from AES. Whereas the spatial resolution of XPS is at best a few micrometers, Auger spectra can be obtained from spots with diameters as small as a few nanometers. It would be extremely interesting to have oxidation state information on the same scale as well  

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