Möss·bau·er effect 
(mœsbou′ər, môs-, mŏs-)
(mœsbou′ər, môs-, mŏs-)n.
The recoilless emission of gamma rays by radioactive nuclei of crystalline solids, and the subsequent absorption of the emitted rays by other nuclei.
[After Rudolf Ludwig Mössbauer (1929-2011), German physicist.]