Which physicist discovered the Mössbauer effect in 1958?

Rudolf Mössbauer discovered the Mössbauer effect in 1958.

The effect is the recoil-free emission and absorption of gamma rays by atomic nuclei bound in a solid. In ordinary emission, a nucleus recoils and slightly changes the energy of the radiation. In a solid lattice, the recoil can instead be absorbed by the entire crystal, allowing extremely precise measurements of nuclear energy levels.

Mössbauer made the discovery while conducting doctoral research at the Technical University of Munich. It became the basis of Mössbauer spectroscopy, which has been used to study chemical bonding, magnetic materials, minerals and gravitational effects on radiation.

He shared the 1961 Nobel Prize in Physics with Robert Hofstadter. The prize citation recognized his discovery of the effect and his research connected with it. The effect also helped confirm a prediction of general relativity in the famous Pound–Rebka experiment.