Grigory Samuilovich Landsberg (Russian: Григорий Самуилович Ландсберг; 22 January 1890 – 2 February 1957) was a Soviet

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

who worked in the fields of

optics Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of optical instruments, instruments that use or Photodetector, detect it. Optics usually describes t ...

and

spectroscopy Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Spectro ...

. Together with

Leonid Mandelstam Leonid Isaakovich Mandelstam or Mandelshtam ( rus, Леонид Исаакович Мандельштам, p=lʲɪɐˈnʲit ɨsɐˈakəvʲɪtɕ mənʲdʲɪlʲˈʂtam, a=Ru-Leonid_Mandelstam.ogg, links=y; 4 May 1879 – 27 November 1944) was a So ...

he co-discovered inelastic combinational scattering of light, which is known as

Raman scattering In chemistry and physics, Raman scattering or the Raman effect () is the inelastic scattering of photons by matter, meaning that there is both an exchange of energy and a change in the light's direction. Typically this effect involves vibrationa ...

Vitae

Landsberg graduated from the

Moscow State University Moscow State University (MSU), officially M. V. Lomonosov Moscow State University,. is a public university, public research university in Moscow, Russia. The university includes 15 research institutes, 43 faculties, more than 300 departments, a ...

in 1913 and then taught there from 1913 to 1915, 1923–1945, and 1947–1951 (Professor since 1923). From 1934, he simultaneously worked also in the Physical Institute of the Academy of Sciences of the USSR. From 1951 to 1957 he was a professor at the

Moscow Institute of Physics and Technology Moscow Institute of Physics and Technology (MIPT; , also known as PhysTech), is a public university, public research university located in Moscow Oblast, Russia. It prepares specialists in theoretical physics, theoretical and applied physics, ...

. Landsberg conducted pioneering studies on the vibrational scattering of light in crystals beginning in 1926. In 1928, Landsberg and Mandelstam discovered a phenomenon of ''combinational scattering of light'' (this phenomenon became known as Raman scattering or the Raman effect independently discovered by C. V. Raman and

K. S. Krishnan Sir Kariamanikkam Srinivasa Krishnan (4 December 1898 – 14 June 1961) was an Indian physicist. He was a co-discoverer of Raman scattering, for which his mentor C. V. Raman was awarded the 1930 Nobel Prize in Physics. Early life Kariama ...

in liquids). Landsberg discovered the

fine structure In atomic physics, the fine structure describes the splitting of the spectral lines of atoms due to electron spin and relativistic corrections to the non-relativistic Schrödinger equation. It was first measured precisely for the hydrogen atom ...

Rayleigh scattering Rayleigh scattering ( ) is the scattering or deflection of light, or other electromagnetic radiation, by particles with a size much smaller than the wavelength of the radiation. For light frequencies well below the resonance frequency of the scat ...

. In 1931, he discovered a phenomenon of selective scattering of light. He laid the foundation for the spectroscopy of organic molecules and the studies on inter- and intra-molecular interactions in the gaseous, liquid and solid phases in the USSR. He founded a major school on atomic and molecular spectral analysis. He developed techniques for the spectral analysis of metals and alloys (USSR Government Prize, 1941), and for the analysis of complex organic mixtures, including motor fuels. He is the author of the famous course of "Optics", and editor of the most popular "Elementary Textbook on Physics" (Volumes 1–3, 7th Edition, 1971). In 1946 he became a full member of the

Soviet Academy of Sciences The Academy of Sciences of the Soviet Union was the highest scientific institution of the Soviet Union from 1925 to 1991. It united the country's leading scientists and was subordinated directly to the Council of Ministers of the Soviet Union (un ...

. He later founded the Commission on Spectroscopy at the academy, which in 1968 was transformed into the Institute for Spectroscopy Russian Academy of Sciences. Landsberg was awarded two

Orders of Lenin The Order of Lenin (, ) was an award named after Vladimir Lenin, the leader of the October Revolution. It was established by the Central Executive Committee on 6 April 1930. The order was the highest civilian decoration bestowed by the Soviet ...

and several medals.

Discovery of the combinational scattering of light

Beginning in 1926, Mandelstam and Landsberg initiated experimental studies on the vibrational scattering of light in crystals at the

. Their intention was to prove the theoretical prediction made by Mandelstam in 1918 regarding the

splitting in Rayleigh scattering due to light scattering on thermal acoustic waves. As a result of this research, Landsberg and Mandelstam discovered the effect of the inelastic combinational scattering of light on 21 February 1928 (''"combinational"'' – from the combination of frequencies of photons and molecular vibrations). They presented this fundamental discovery for the first time at a colloquium on 27 April 1928. They published brief reports about this discovery (experimental results with theoretical explanation) in Russian and in German and then published a comprehensive paper in ''

Zeitschrift für Physik ''Zeitschrift für Physik'' (English: ''Journal for Physics'') is a defunct series of German peer-reviewed physics journals established in 1920 by Springer Berlin Heidelberg. The series ended publication in 1997, when it merged with other journal ...

''. In the same year of 1928, two Indian scientists C. V. Raman and K. S. Krishnan were looking for the "Compton component" of scattered light in liquids and vapors. They found the same combinational scattering of light. Raman stated that "The line spectrum of the new radiation was first seen on 28 February 1928." Thus, combinational scattering of light was discovered by Mandelstam and Landsberg a week earlier than by Raman and Krishnan. However, the phenomenon became known as the Raman effect because Raman published his results earlier than Landsberg and Mandelstam did. Nonetheless, in Russian-language literature, it is traditionally called ''"combinational scattering of light"''.

References

{{DEFAULTSORT:Landsberg, Grigory Samuilovich 1890 births 1957 deaths People from Vologda People from Vologodsky Uyezd Jewish Russian scientists Russian physicists Soviet inventors Soviet Jewish physicists Moscow State University alumni Academic staff of the Moscow Institute of Physics and Technology Full Members of the USSR Academy of Sciences Russian scientists