A phenomenon that today allows scientists to quickly detect illegal drugs without tampering with the packaging, to analyze nuclear waste from safe distances and to detect life-threatening diseases at an early stage will be designated an International Historic Chemical Landmark by the world's largest scientific society -- the American Chemical Society -- and the Indian Association for the Cultivation of Science (IACS). The ceremony takes place Dec. 15 in Calcutta, India.
Called the Raman effect, this phenomenon involves the scattering of light by liquids, solids or gases, in such a way that a very small fraction of the reflected light is a different color than the incident light. It was discovered by Professor C.V. Raman of Calcutta University, who challenged the idea that the color of the sea was simply a reflection of the blue sky, while crossing the Mediterranean on a 15-day voyage from London to Bombay. Instead, he found that it resulted from the scattering of sunlight by water molecules.
Subsequent extensive studies on light-scattering led Raman to discover in 1928 a new kind of light-scattering for which he was awarded the Nobel Prize in Physics two years later. The international landmark designation marks 70 years of employing Raman's work in numerous applications and now the Raman spectrometer, coupled with today's lasers and computer, is an analytical method for studying unknown materials. It detects molecular motion, especially vibrations, and correlates that with molecular structure, providing a "fingerprint" of the material being studied.
ACS President-elect Edel Wasserman said, "Today, the American Chemical Society and the Indian Association for the Cultivation of Science join in honoring Raman's research in Calcutta that had a great impact on chemistry and physics. In doing so, we not only commemorate a key discovery, we also honor the long and proud history of the scientific enterprise in India."
A commemorative plaque will be presented at the Indian Association for the Cultivation of Science. It reads:
"At this institute, Sir C.V. Raman discovered in 1928 that when a beam of coloured light entered a liquid, a fraction of the light scattered by the liquid was of a different colour. Raman showed that the nature of this scattered light was dependent on the type of sample present. Other scientists quickly understood the significance of this phenomenon as an analytical and research tool and called it the Raman effect. This method became even more valuable with the advent of modern computers and lasers. Its current uses range from the non-destructive identification of minerals to the early detection of life-threatening diseases. For his discovery Raman was awarded the Nobel Prize in physics in 1930."
The American Chemical Society started the National Historic Chemical Landmark Program in 1992. During the International Chemistry Celebration, which runs through November 1999, the landmarks program has now been extended internationally. The Indian Association for the Cultivation of Science has joined the American Chemical Society in designating the Raman effect an Historic Chemical Landmark.