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The Gist of Science Reporter: February 2014

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The significance of the Raman Effect was recognized quickly by scientists all over the world. Professor RW. Wood of Johns Hopkins cabled Nature to report that he had verified Raman’s “brilliant and surprising discovery” in detail. He declared that this discovery which resulted from Raman’s long and patient study of the phenomenon of light scattering is one of the most convincing proofs of the quantum theory.

When people made comparisons to the well known Compton effect, Raman prophetically stated that his effect which involved molecular scattering would have greater implications than the Compton scattering, which had to dowith electron scattering of photon.

Raman also recognized that his discovery was important to firmly establish the new quantum theory; because an explanation of the new radiation required the use of photons and their change in energy as they interacted with the atoms in a particular molecule. Raman also knew that there was a more important result, remarking in his 1930 Nobel Prize address that “ ... the character of the scattered radiations enables us to obtain an insight into the ultimate structure of the scattering substance.”

By the late 1930s, the Raman Effect became an important method of nondestructive chemical analysis for both organic and inorganic compounds. The unique spectrum of Raman scattered light for any particular substance served as a “fingerprint” that could be used for qualitative analysis, even in a mixture of materials. Further, the intensity of the spectral lines was related to the amount of the substance. Raman spectroscopy could be applied not only to liquids but also to gases and solids. And unlike many other analytical methods, it could be applied easily to the analysis of aqueous solutions. It was a ubiquitous technique, giving information on what and how much was present in a wide variety of samples.

The use of Raman spectroscopy as a basic analytical tool changed sharply after World War II. During the War, infrared spectroscopy was enhanced by the development of sensitive detectors and advances in electronics. Infrared measurements quickly became routine operations, while Raman measurements still required skilled operators and darkroom facilities. Raman spectroscopy was sidelined for a while because of Infrared spectroscopy. But with the advent of another great discovery in the 1960s, that of laser, interest in Raman spectroscopy was again revived. Now it finds application in many diverse fields like medical imaging and Biochemistry.

He was knighted by the British government in India and received the Nobel Prize in physics in 1930 (among all the Nobel Prizes awarded, this must have been the shortest in duration from the time of discovery).

Three years later, Raman left Calcutta for Bangalore, where he was posted as the Director of the Indian Institute of Science (the first Indian to hold the post which was dominated by the British; his knighthood must have made it possible). There he continued his work on the Raman Effect and became interested in the structure of crystals, especially diamond.

In 1934, he founded the Indian Academy of Science and began the publication of its Proceedings.