- Auger effect
The Auger effect (pronEng|ˈɔːʒɚ, or Oh' jeh) is a phenomenon in
physics in which the emission of anelectron from anatom causes the emission of a second electron. [GoldBookRef|title=Auger effect|url=http://goldbook.iupac.org/A00520.html] When anelectron is removed from a core level of anatom , leaving a vacancy, an electron from a higher energy level may fall into the vacancy, resulting in a release ofenergy . Although sometimes this energy is released in the form of an emittedphoton , the energy can also be transferred to another electron, which is ejected from the atom. This second ejected electron is called an Auger electron. [GoldBookRef|title=Auger electron|url=http://goldbook.iupac.org/A00521.html]Upon ejection the
kinetic energy of the Auger electron corresponds to the difference between the energy of the initialelectronic transition and theionization energy for theelectron shell from which the Auger electron was ejected. These energy levels depend on the type of atom and the chemical environment in which the atom was located.Auger electron spectroscopy involves the emission of Auger electrons by bombarding a sample with eitherX-ray s or energetic electrons and measures the intensity of Auger electrons as a function of the Auger electron energy. The resulting spectra can be used to determine the identity of the emitting atoms and some information about their environment.Auger recombination is a similar Auger effect which occurs insemiconductor s. An electron andelectron hole (electron-hole pair) can recombine giving up their energy to an electron in the conduction band, increasing its energy. The reverse effect is known asimpact ionization .The name "Auger effect" comes from one of its discoverers,
Pierre Victor Auger , and not from the similarly-named device, theauger .Discovery
The Auger emission process was discovered in the 1920s by
Lise Meitner , an Austrian physicist. The Auger effect was discovered in 1925 byPierre Victor Auger upon analysis of a Wilsoncloud chamber experiment. High energy X-rays were applied to ionize gas particles and observephotoelectric electrons. Observation of electron tracks independent of the frequency of the incident photon energy suggested a mechanism for electron ionization that was caused from aninternal conversion of energy of from a radiationless transition. Further investigation and theoretical work showed that the effect was a radiationless effect more than an internal conversion effect by use of elementary quantum mechanics and transition rate and transition probability calculations. (ref 1)See also
*Charge carrier generation and recombination
*Auger electron spectroscopy References
*"The Auger Effect and Other Radiationless Transitions". Burhop, E.H.S., Cambridge Monographs on Physics, 1952
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