Auger effect

Two-electron process in which a weakly bound electron passes to a lower-energy, unoccupied state. The energy released in the process is transferred to another weakly bound electron of the same atom, which is then emitted from the atom (Auger electron). The Auger Electron Spectroscopy (AES) is based on the Auger effect. It is a method for characterising near-surface atoms and their binding state, especially "light" elements such as carbon, nitrogen and boron.