Noun
the resonance absorption of a gamma ray by a nucleus identical to the nucleus that emitted the gamma ray
Source: WordNetHowever, attempts to observe nuclear resonance produced by gamma-rays in gases failed due to energy being lost to recoil, preventing resonance (the Doppler effect also broadens the gamma-ray spectrum). Source: Internet
The Mössbauer effect, or recoilless nuclear resonance fluorescence, is a physical phenomenon discovered by Rudolf Mössbauer in 1958. Source: Internet