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Encyclopedia > Internal conversion
Nuclear processes

Most internal conversion electrons come from the K shell, as this electron has the highest probability of being found inside the nucleus. After the electron has been emitted, the atom is left with a vacancy in one of the inner electron shells. This hole will be filled with an electron from one of the higher shells and subsequently a characteristic x-ray or Auger electron will be emitted. Auger emission (pronounced ) is a phenomenon in physics in which the emission of an electron from an atom causes the emission of a second electron. ...

Internal conversion is favoured when the energy gap between nuclear levels is small, and is also the only mode of de-excitation for 0+ -> 0+ (i.e. E0) transitions (i.e., where exited nuclei are able to rid themselves of energy without changing electric and magnetic moments in certain ways). It is the predominant mode of de-excitation whenever the initial and final spin states are the same, but the multi-polarity rules for nonzero initial and final spin states do not necessarily forbid the emission of a gamma ray in such a case. In physics, spin refers to the angular momentum intrinsic to a body, as opposed to orbital angular momentum, which is the motion of its center of mass about an external point. ... In electrodynamics, polarization (also spelled polarisation) is the property of electromagnetic waves, such as light, that describes the direction of their transverse electric field. ...

The tendency towards internal conversion can be determined by the internal conversion coefficient, which is empirically determined by the ratio of de-excitations that go by the emission of electrons to those that go by gamma emission. The internal conversion coefficient may be empirically determined by the following formula: = # de-excitations via electron emission / # de-excitations via gamma-ray emission There is no valid conversion coefficient for E0 transitions. ... Results from FactBites:

 Internal conversion - Wikipedia, the free encyclopedia (360 words) Internal conversion is a radioactive decay process where an excited nucleus interacts with an electron in one of the lower electron shells causing the electron to be emitted. The internal conversion process is not actually the photoelectric ejection of an atomic electron, as the nucleus does not actually emit a gamma ray in the first place in this process. The tendency towards internal conversion can be determined by the internal conversion coefficient, which is empirically determined by the ratio of de-excitations that go by the emission of electrons to those that go by gamma emission.
 Mills, William Raymond (1955-01-01) Absolute measurements of internal conversion coefficients. ... (384 words) The combination of conversion electron and gamma yield measurements constitutes an experimental determination of an internal conversion coefficient, and by comparison with theory it is possible to make gamma-ray multipole order assignments. We have measured the conversion coefficients and found the 1.06-Mev line to be M4 with E2 indicated for the 0.57-Mev line. We have measured the conversion coefficient of the 440-kev transition and assign it either E1 or M1, the experimental uncertainties preventing a definite assignment.
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