Other Free Encyclopedias » Online Encyclopedia » Encyclopedia - Featured Articles » Contributed Topics from K-O

Mössbauer, Rudolph Ludwig

gamma ray effect wavelength

[moes bower] (1929–) German physicist: discovered the Mössbauer effect, which he used to verify Einstein’s general relativity theory.

Mössbauer was taking his doctorate at the Max Planck Institute for Medical Research in Heidelberg (1955–7) when he discovered what is now called the Mössbauer effect. When an atom absorbs a gamma ray it recoils and, by energy conservation, the wavelength of the re-emitted gamma ray is altered. However, Mössbauer found that at low temperatures one can avoid (for a certain fraction of gamma ray processes) the excitation of vibrational motions in a solid. In such processes, the lattice recoils as a whole and recoil shifts of the energy are absent in the associated gamma-lines; in effect recoil-less nuclear resonance provides very high precision (1 in 10 12 ) in the absorbed and re-emitted gamma ray wavelength. This precision allows detection of different electronic environments surrounding particular nuclei (Mössbauer spectroscopy). Thus Fe 2+ and Fe 3+ can be separately detected in Fe3O4 . Also, general relativity theory was verified by measuring the change in wavelength of a gamma ray due to its moving from one point of gravitational potential to another (1960).

Mössbauer shared the 1961 Nobel Prize for physics, and afterwards held professorships at the California Institute of Technology (until 1965) and at Munich.

Ma, Jack - Chief Executive Officer of Alibaba.com, Career, Sidelights [next] [back] Müller, Paul Hermann

User Comments

Your email address will be altered so spam harvesting bots can't read it easily.
Hide my email completely instead?

Cancel or