Rudolf Mössbauer

Born in Munich on 31 January 1929, Rudolf Mössbauer was a German physicist and Nobel laureate known for his discovery of recoilless nuclear resonance fluorescence, known as the Mössbauer effect . He discovered the effect in 1957, while pursuing graduate studies in physics at the Technical University of Munich. During his doctoral research there, which focused on the emission and absorption of gamma rays in solids, he found that, at low temperature, nuclei of iridium-191 embedded in a crystal lattice can emit or absorb gamma rays without losing energy to nuclear recoil. The effect proved to be a useful spectroscopy tool for many fields in physics and chemistry. By the time he was awarded the 1961 Nobel Prize in Physics at age 32, Mössbauer had completed his PhD and was working as a professor at Caltech. In 1965 he returned to the Technical University of Munich, where he served as a professor of physics until his retirement as professor emeritus in 1997, except for a short period (1972–77) when he went to France to head the Institut Laue–Langevin in Grenoble. During his Munich years, he focused on low-energy neutrino physics, particularly neutrino oscillation and solar neutrino experiments. Mössbauer died in 2011 at age 82. (Photo credit: AIP Emilio Segrè Visual Archives, Physics Today Collection)

Date in History: 31 January 1929