page_title: C. V. Raman
section_title: The scattering experiments
hierarchical_section_title: C. V. Raman / Scientific contributions / Raman effect / The scattering experiments
caption_attribution_description: English: Raman spectrum of Benzene showing both Stokes and anti-Stokes lines around the exciting 4358.3 angstrom line. Originally published in Nature in 1929 by Raman and Krishnan.
context_page_description: Sir Chandrasekhara Venkata Raman was an Indian physicist who made groundbreaking works in the field of light scattering. With his student K. S. Krishnan, he discovered that when light traverses a transparent material, some of the deflected light change wavelength and amplitude. This phenomenon was a new type of scattering of light and was subsequently known as the Raman effect. Raman won the 1930 Nobel Prize in Physics and was the first non-European, Indian or Asian person to receive a Nobel Prize in any branch of science.
  Born to Hindu Tamil Brahmin parents, Raman was a precocious child, completing his secondary and higher secondary education from St Aloysius' Anglo-Indian High School at the ages of 11 and 13, respectively. He topped bachelor's degree examination at the University of Madras with honours in physics from Presidency College at age 16. His first research paper, on diffraction of light, was published in 1906 while still a graduate student. The next year he obtained an M.A. degree. He was 19 years of age when he joined the Indian Finance Service in Kolkata as Assistant Accountant General.
context_section_description: Krishnan started the experiment at the beginning of January 1928. On 7 January Krishnan discovered that no matter what kind of pure liquid he used, it always produced polarised fluorescence within the visible spectrum of light. As Raman saw the result, he was astonished why he never observed such phenomenon all those years. That night they named the new phenomenon as "modified scattering" with reference to the Compton effect as unmodified scattering. On 16 February they sent a manuscript to Nature titled "A new type of secondary radiation", which was published on 31 March.
  On 28 February 1928, Raman and Krishnan obtained spectra of the modified scattering separate from the incident light. Due to difficulty in measuring wavelengths of light, they had been relying on visual observation of the colour produced from sunlight through prism. Raman had invented an instrument for detecting and measuring electromagnetic waves called a spectrograph. That moment they could employ the instrument using monochromatic light from a mercury arc lamp which penetrated transparent material and was allowed to fall on a spectrograph to record its spectrum. The lines of scattering could now be measured and photographed.
caption: An early Raman spectrum of benzene published by Raman and Krishnan.[74]
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