Ordinarily, when an atom emits a gamma ray, it recoils. The wavelength of the gamma ray depends in part on the extent of this recoil. Since this varies somewhat from atom to atom, the gamma rays emitted show a spread of wavelength.
The German physicist Rudolf Ludwig Mossbauer (b. 1929) studied conditions under which atoms that were part of a crystal would emit a gamma ray in such a way that the recoil would be spread over all the atoms making up the crystal.
The recoil is then vanishingly slight, and the gamma ray wavelength shows no spread due to that recoil. As a result, the crystal emits a sharply monochromatic beam of gamma rays, and this, discovered in 1958, is called the Mossbauer effect.
Gamma rays emitted in this way by one crystal will be easily absorbed by another crystal of the same type, but if the wavelength varies even slightly in either direction, absorption will not take place. For this work, Mossbauer received a share of the Nobel Prize for physics in 1961.
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|Publication:||Asimov's Chronology of Science & Discovery, Updated ed.|
|Article Type:||Reference Source|
|Date:||Jan 1, 1994|
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