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单词 Raman effect
释义
Raman effect

Physics
  • A type of scattering of electromagnetic radiation in which light suffers a change in frequency and a change in phase as it passes through a material medium. The intensity of Raman scattering is about one-thousandth of that of Rayleigh scattering in liquids; for this reason it was not discovered until 1928. The development of the laser led to the Raman effect being used very extensively.

    In Raman spectroscopy light from a laser is passed through a substance and the scattering is analysed spectroscopically. The new frequencies in the Raman spectrum of monochromatic light scattered by a substance are characteristic of the substance. Both inelastic and elastic scattering occur. The technique is used as a means of determining molecular structure and as a tool in chemical analysis. The effect was discovered by the Indian scientist Sir Chandrasekhara Venkata Raman (1888–1970). It was also discovered in 1928 by Leonid Mandelstam and Grigory Landsberg. It was predicted theoretically by Adolf Smekal in 1923 and by Hendrik Kramers and Werner Heisenberg in 1925.

    http://www.uky.edu/~holler/raman.html The original paper in Nature (1928) by Raman and Krishnan


Astronomy
  • The scattering of a photon by an atom or molecule that is accompanied by an excitation (or de-excitation) of the atom or molecule, and hence a change in the wavelength of the photon. It is named after the Indian physicist Chandrasekhara Venkata Raman (1888–1970), who discovered it in 1928. The effect can be important in the spectra of molecules.


Chemistry
  • A type of scattering of electromagnetic radiation in which light suffers a change in frequency and a change in phase as it passes through a material medium. The intensity of Raman scattering is about one-thousandth of that in Rayleigh scattering in liquids; for this reason it was not discovered until 1928. However, it was not until the development of the laser that the effect was put to use in an extensive way.

    In Raman spectroscopy light from a laser is passed through a substance and the scattering is analysed spectroscopically. The new frequencies in the Raman spectrum of monochromatic light scattered by a substance are characteristic of the substance. Both inelastic and superelastic scattering occurs. The technique is used as a means of determining molecular structure and as a tool in chemical analysis. The effect was discovered by the Indian scientist Sir Chandrasekhara Venkata Raman (1888–1970), having been predicted theoretically using quantum theory by Werner Heisenberg and Hendrik Kramers in 1925.

    http://www.uky.edu/~holler/raman.html The original paper by Raman and Krishnan


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