Lamb–Mössbauer factor
Encyclopedia
In physics, the Lamb–Mössbauer factor (LMF, after Willis Lamb
and Rudolf Mössbauer) or elastic incoherent structure factor (EISF) is the ratio of elastic to total incoherent neutron scattering
, or the ratio of recoil-free to total nuclear resonant absorption in Mössbauer spectroscopy. The corresponding factor for coherent
neutron or X-ray scattering is the Debye–Waller factor; often, that term is used in a more generic way to include the incoherent case as well.
When first reporting on recoil-free resonance absorption, Mössbauer (1959) cited relevant theoretical work by Lamb (1939). The first use of the term "Mössbauer–Lamb factor" seems to be by Tzara (1961); from 1962 on, the form "Lamb–Mössbauer factor" came into widespread use.
Singwi and Sjölander (1960) pointed out the close relation to incoherent neutron scattering. With the invention of backscattering spectrometers
, it became possible to measure the Lamb–Mössbauer factor as a function of the wavenumber
(whereas Mössbauer spectroscopy operates at a fixed wavenumber). Subsequently, the term elastic incoherent structure factor became more frequent.
Willis Lamb
Willis Eugene Lamb, Jr. was an American physicist who won the Nobel Prize in Physics in 1955 together with Polykarp Kusch "for his discoveries concerning the fine structure of the hydrogen spectrum". Lamb and Kusch were able to precisely determine certain electromagnetic properties of the electron...
and Rudolf Mössbauer) or elastic incoherent structure factor (EISF) is the ratio of elastic to total incoherent neutron scattering
Neutron scattering
Neutron scattering,the scattering of free neutrons by matter,is a physical processand an experimental technique using this processfor the investigation of materials.Neutron scattering as a physical process is of primordial importance...
, or the ratio of recoil-free to total nuclear resonant absorption in Mössbauer spectroscopy. The corresponding factor for coherent
Coherence (physics)
In physics, coherence is a property of waves that enables stationary interference. More generally, coherence describes all properties of the correlation between physical quantities of a wave....
neutron or X-ray scattering is the Debye–Waller factor; often, that term is used in a more generic way to include the incoherent case as well.
When first reporting on recoil-free resonance absorption, Mössbauer (1959) cited relevant theoretical work by Lamb (1939). The first use of the term "Mössbauer–Lamb factor" seems to be by Tzara (1961); from 1962 on, the form "Lamb–Mössbauer factor" came into widespread use.
Singwi and Sjölander (1960) pointed out the close relation to incoherent neutron scattering. With the invention of backscattering spectrometers
Neutron backscattering
Neutron backscattering is one of several inelastic neutron scattering techniques. Backscattering from monochromator and analyzer crystals is used to achieve an energy resolution in the order of μeV...
, it became possible to measure the Lamb–Mössbauer factor as a function of the wavenumber
Wavenumber
In the physical sciences, the wavenumber is a property of a wave, its spatial frequency, that is proportional to the reciprocal of the wavelength. It is also the magnitude of the wave vector...
(whereas Mössbauer spectroscopy operates at a fixed wavenumber). Subsequently, the term elastic incoherent structure factor became more frequent.