Auger effect

The Auger effect (/oʊˈʒeɪ/; French pronunciation: [ˈ/o.ʒe/]) or Auger−Meitner effect is a physical phenomenon in which atoms eject electrons. It occurs when an inner-shell vacancy in an atom is filled by an electron, releasing energy that causes the emission of another electron from a different shell of the same atom.^[1]

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. For light atoms (Z<12), this energy is most often transferred to a valence electron which is subsequently ejected from the atom.^[2] This second ejected electron is called an Auger electron.^[3] For heavier atomic nuclei, the release of the energy in the form of an emitted photon becomes gradually more probable.