When light is scattered from an atom or molecule, most photons are elastically scattered. The scattered photons have the same energy and, therefore, wavelength, as the happening photons. However, a small fraction of scattered light approximately 1 in 10 million photons is scattered from excitations with optical frequencies different from, and usually lower than, the frequency of the incident photons. In a gas inelastic scattering of a photon can occur with a change in vibrational, rotational or electronic energy of a molecule. This effect was first reported by C.V.Raman and K.S.Krishnan and independently by Grigory Lansberg and Leonid Mandelstam in 1928. Chandrasekhara Venkata was born on Nov7, 1888. Raman received the Nobel Prize in 1930 for this work. His work have been named after his name `Raman effect`. In 1998 the Raman Effect was designated an ACS National Historical Chemical Landmark in recognition of its significance as a tool for analyzing the composition of liquids, gases, and solids.

Chandrasekhara Venkata Raman was born at Trichinopoly in Southern India on 7th November, 1888. His father was a lecturer in mathematics and physics and so from the first he was emerged in an academic atmosphere. CV Raman is the uncle of three world renowned Physicists Subrahmanyan Chandrasekhar Nobel laureate, Sivaramakrishna Chandrasekhar FRS, known for Liquid crystal research and Sivaraj Ramaseshan, ex director of Indian Institute of Science. Sir C.V. Raman died on 21st November 1970. He entered Presidency College, Madras in 1902 and in 1904 passed his B.A. examination, winning the first place and the gold medal in physics. In 1907 he gained his M.A. degree with the highest distinctions. Then he joined the Indian Finance Department as an Assistant Accountant General in Calcutta. During his days in Calcutta, Raman found opportunities for carrying on experimental research in the laboratory of the Indian Association for the Cultivation of Science at Calcutta of which he became Honorary Secretary in 1919. In 1917 C.V Raman resigned from his government job and took up Palit Professorship in Physics at the University of Calcutta. To him, this period was the golden era of his career.

During his tenure in Calcutta, he received worldwide recognition for his work in optics and scattering of light. He was elected to the Royal Society of London in 1924 and the British made him a knight of the British Empire in 1929. In the same year C.V.Raman was honored with the president`s chair of the 16th Session of the Indian Science Congress. The following year he was honored with the prestigious Hughes medal from the Royal Society. His research work in the Indian Association for the Cultivation of Science culminated with his Nobel Prize winning work. In the year 1930 C.V.Raman won the Nobel Prize for his work on the scattering of light and for the discovery of the `Raman effect`. For the first time in its history, an Indian scholar has received the highest honor in science. When he was offered a toast during the Nobel function being a strict abstains completely from alcoholic beverages he responded "Sir, you have seen the Raman effect on alcohol; please do not try to see the alcohol effect on Raman".

`Raman Spectroscopy` is based on this phenomenon. `Raman spectroscopy` is a spectroscopic technique used in condensed matter physics and chemistry to study vibrational, rotational, and other low-frequency modes in a system. Raman also worked on the acoustics of musical instruments. He worked out the theory of `transverse vibration` of bowed strings, on the basis of `superposition velocities`. Hermann Ludwig Ferdinand von Helmholtz ,German physician and physicist have also worked on it but Raman`s work does a better job in explaining bowed string vibration over Helmholtz`s approach. He was also the first to investigate the harmonic nature of the sound of the Indian drums such as the tabla and the mridangam.

After 15 years at Calcutta in 1934 he became the director of the newly established `Indian Institute of Science` at Bangalore. Two years later he continued as a professor of Physics there. Raman along with Dr. Krishnamurthy in 1943 started a company called Travancore Chemical and Manufacturing Co. Ltd.which during its 60 year history, established 4 factories in Southern India.C.V.Raman was appointed as the first National professor in the year 1947 by the new government of Independent India. He retired from the Indian Institute in 1948 and a year later he established the Raman Research Institute in Bangalore. Raman remained active with his institute until his death.

He also founded the Indian Journal of Physics in 1926, of which he is the Editor. Raman sponsored the establishment of the Indian Academy of Sciences and endowed as the President since its origin. He also initiated the Proceedings of that academy, in which much of his work has been published, and is President of the Current Science Association, Bangalore, which publishes Current Science (India).

Raman`s earliest researches in optics and acoustics, the two fields of investigation to which he has dedicated his entire career were carried out while he was a student. Some of Raman`s early memoirs appeared as Bulletins of the Indian Association for the Cultivation of Science dealing with the "Maintenance of Vibrations" and with the theory of the musical instruments of the violin family. He contributed an article on the theory of musical instruments to the 8th Volume of the Handbuch der Physik, 1928. In 1922 he published his work on the "Molecular Diffraction of Light", the first of a series of investigations with his collaborators. This ultimately led to his discovery, on the 28th of February, 1928, of the radiation effect which bears his name and which gained him the 1930 Nobel Prize in Physics.

Other investigations carried out by Raman were: his experimental and theoretical studies on the diffraction of light by acoustic waves of ultrasonic and hypersonic frequencies, and those on the effects produced by X-rays on infrared vibrations in crystals exposed to ordinary light. In 1948 Raman, through studying the spectroscopic behaviour of crystals, approached in a new manner fundamental problems of crystal dynamics. His laboratory has been dealing with the structure and properties of diamond, the structure and optical behaviour of numerous iridescent substances (labradorite, pearly felspar, agate, opal, and pearls). Among his other interests have been the optics of colloids, electrical and magnetic anisotropy, and the physiology of human vision.

Raman has been honoured with a large number of honorary doctorates and memberships of scientific societies. He was awarded the Bharat Ratna in 1954 and with the Lenin Peace Prize in 1957. India celebrates National Science Day on the 28th February of every year to honor the memory of Raman`s discovery in 1928.