Auger effect
Auger effect is a spontaneous process in which inner shell vacancy of a atom filled
by a electron from outer shell.
The auger effect is a process by which electron with characteristic energy are
ejected from the atoms in response to down word transition by another electron in
the atom. In auger effect the vacancy is produced bombardment with high energy
electrons, but the auger effect can occur if the vacancy produced by other
interactions.
If an inner shell electron is removed from an atom, an electron from a higher level
will quickly make the transition down word to fill the vacancy. Some times this
transition will be accompanied by an emitted photon whose quantum energy
matches the energy gap between the upper and lower level. Since for heavy atoms
this quantum energy will be in the x-ray level, it is commonly called x-ray
fluorescence. This emission process for lighter atoms and outer electrons gives rise
to line spectra.
DISCOVERY
The Auger emission process was discovered in the 1920s by Lise Meitner, an
Austrian physicist. The Auger effect was discovered in 1925 by Pierre Victor
Auger upon analysis of a Wilson cloud chamber experiment. High energy X-
rays were applied to ionize gas particles and observe photoelectric electrons.
Observation of electron tracks independent of the frequency of the incident
photon energy suggested a mechanism for electron ionization that was caused
from an internal 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.
