The
Auger effect is a physical phenomenon in which the filling of an
inner-shell vacancy of an
atom is accompanied by the emission of an
electron from the same atom. When a
core electron is removed, leaving a vacancy, an electron from a higher energy level may fall into the vacancy, resulting in a release of
energy. Although most of the time this energy is released in the form of an emitted
photon, the energy can also be transferred to another electron, which is ejected from the atom. This second ejected electron is called an
Auger electron, after one of its discoverers,
Pierre Victor Auger.