Internal conversion

Article By:

Hamilton, Joseph H. Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee.

Last reviewed:August 2020

DOI:https://doi.org/10.1036/1097-8542.349550

A process in which an excited nucleus transfers its excitation energy directly to an atomic electron in one of the allowed electron energy states, and the electron (termed an internal conversion electron) is ejected from the atom. This process of transferring the nuclear excitation energy to an atomic electron competes with gamma-ray emission to de-excite the nucleus. The internal conversion electron has an energy E_i = W − B_i, where W is the nuclear transition energy between the initial and final nuclear states (W = hυ of the competing gamma ray with frequency υ, where h is Planck's constant) and B_i is the binding energy of the electron in the ith shell, for example, K, L (L_I, L_II, L_III), M, and so forth. Because electrons can be ejected from several different shells and subshells, their spectra are more complex than gamma-ray spectra, where only one gamma ray is observed for each transition with the total energy W. See also: Atomic structure and spectra; Gamma rays

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