Raman, Chandrasekhara Venkata (1888-1970)

Indian physicist who was awarded the Nobel Prize for Physics in 1930 for his discovery in 1928 of what became known as the Raman effect: the scattering of monochromatic (single-wavelength) light when passed through a transparent substance. The Raman spectra produced are used to obtain information on the structure of molecules. He was knighted in 1929.

Raman was born in Trichinopoly, Madras (now Chennai), and studied at Madras. He joined the civil service as an accountant in Calcutta (now Kolkata) but pursued his studies privately. His work on vibration in sound and the theory of musical instruments and on diffraction led to his becoming professor of physics at the University of Calcutta 1917-33. From 1948 he was director of the Raman Research Institute, built for him by the government in Bangalore.

Raman showed in 1921 that the blue colour of the sea is produced by the scattering of light by water molecules. Continuing to work on the scattering of light, he arrived at the Raman effect. It is caused by the internal motion of the molecules encountered, which may impart energy to the light photons or absorb energy in the resulting collisions. Raman scattering therefore gives precise information on the motion and shape of molecules.

Raman's other research included the effects of sound waves on the scattering of light in 1935 and 1936, the vibration of atoms in crystals in the 1940s, the optics of gemstones, particularly diamonds, and of minerals in the 1950s, and the physiology of human colour vision in the 1960s.