Sir Chandrasekhara Venkata Raman ( C.V. Raman), FRS (7 November 1888 – 21 November 1970), was an Indian physicist whose groundbreaking work in light scattering earned him international acclaim. Renowned for discovering the Raman effect, his contributions to science have left an indelible mark on the field of physics and beyond.
Born in Tiruchirappalli, Madras Presidency (now Tamil Nadu, India), Raman exhibited exceptional intelligence from a young age. He completed his secondary and higher secondary education at St. Aloysius’ Anglo-Indian High School by the ages of 11 and 13, respectively. At just 16, he graduated with honors in physics from Presidency College, University of Madras, topping his bachelor’s degree examination. Even as an undergraduate, Raman’s potential was evident; his first research paper on the diffraction of light was published in 1906. By the following year, he had earned his master’s degree.
At 19, Raman joined the Indian Finance Service in Calcutta as Assistant Accountant General. There, he discovered the Indian Association for the Cultivation of Science (IACS), India’s first research institute, which provided him with a platform for independent research. His work at IACS led to significant advancements in acoustics and optics, laying the foundation for his future discoveries.
In 1917, Raman was appointed the first Palit Professor of Physics at Rajabazar Science College under the University of Calcutta, thanks to Ashutosh Mukherjee. His first trip to Europe, during which he observed the Mediterranean Sea, inspired him to challenge the prevailing explanation for the sea’s blue color—that it was merely reflected Rayleigh-scattered light from the sky. This observation spurred his investigations into the scattering of light.
Sir C. V. Raman was born on November 7, 1888, in Tiruchirappalli, Madras Presidency (now Tamil Nadu, India), into an Iyer Brahmin family. His parents, Chandrasekhar Ramanathan Iyer and Parvati Ammal, had eight children, and Raman was the second oldest. His father was a school teacher, earning a modest income. Raman humorously recalled, “I was born with a copper spoon in my mouth. At the time of my birth, my father earned a magnificent salary of ten rupees a month!”
Early life
In 1892, the family moved to Visakhapatnam when his father was appointed to the physics faculty at Mrs. A.V. Narasimha Rao College. Raman attended St. Aloysius Anglo-Indian High School in Visakhapatnam. He excelled academically, passing his matriculation exam at the age of 11 and the intermediate exam (equivalent to today’s pre-university course) at 13, both with top honors in the Andhra Pradesh school board.
In 1902, Raman joined Presidency College in Madras (now Chennai), where his father had been transferred to teach mathematics and physics. In 1904, he earned a BA degree from the University of Madras, securing the first place and winning gold medals in physics and English. While still an undergraduate at 18, he published his first scientific paper, “Asymmetrical Diffraction Bands Due to a Rectangular Aperture,” in the British journal Philosophical Magazine in 1906. He completed his MA degree with highest distinction in 1907 from the same university. His second paper, on the surface tension of liquids, was also published in the same journal that year.
Raman’s physics teacher, Richard Llewellyn Jones, recognizing his potential, encouraged him to pursue research in England. However, after a physical examination arranged by Jones, it was determined that Raman’s health was too delicate for the harsh English climate. Reflecting on this, Raman later said, “[Gifford] examined me and certified that I was going to die of tuberculosis if I went to England.”
Career of C.V. Raman
One of the most significant discoveries in light scattering is the Raman Effect, named after Indian physicist C.V. Raman. This discovery built on his earlier work on why the sea looks blue. In 1923, Raman’s experiments showed that when sunlight passed through certain liquids and solids, new light rays appeared in addition to the original light. Initially, Raman and his colleague K.S. Krishnan thought this was a case of “weak fluorescence.”
In 1925, Krishnan noticed an extra scattering line when light passed through a liquid. They called this “feeble fluorescence,” but it took two more years to understand it fully.The major inspiration came from the discovery of the Compton Effect in 1923 by Arthur Compton. Compton showed that electromagnetic waves could also behave like particles, which was widely accepted by 1927. When Compton won the Nobel Prize in Physics in December 1927, Raman was thrilled and told Krishnan that if it was true for X-rays, it should be true for light as well. He predicted they would find a similar effect for light.Raman was also influenced by a 1924 debate in Toronto, where scientists discussed whether light was a wave or a particle. Raman sided with the wave theory but realized there had to be an optical counterpart to the Compton Effect.
The Experiments
Krishnan started experiments in January 1928. On January 7, he observed that any pure liquid always produced polarized light within the visible spectrum. Raman was surprised he hadn’t noticed this before and named it “modified scattering,” similar to the Compton Effect’s “unmodified scattering.”
On February 16, they sent a manuscript titled “A New Type of Secondary Radiation” to the journal Nature, and it was published on March 31, 1928. By February 28, 1928, Raman had obtained spectra showing the modified scattering distinct from the original light.
Raman invented a simple spectrograph to measure this effect. He commented, “When I received the Nobel Prize, I had hardly spent 200 rupees on my equipment,” though the actual costs were higher. Using monochromatic light from a mercury arc lamp, they could now measure and photograph the scattered light’s spectra, confirming the Raman Effect.
Announcement
On the same day, Raman made the announcement in front of the press. The next day, February 29, the Associated Press of India reported it as “A New Principle of Radiation: Prof. Raman’s Discovery.” It presented the story as follows: “Professor C.V. Raman of Calcutta University has made a discovery that promises fundamental significance for physics… The new phenomenon, explored with X-rays by Professor Compton and others, exhibits even more startling features. The main feature observed is that when a substance is excited by light of one color, it emits light of two colors, one of which is distinctly different from the exciting color and lies below the spectrum. Remarkably, the shifted color is quite independent of the nature of the substance used.”
This news was republished on March 1 by The Statesman under the headline “Radiation by Atoms – A New Phenomenon – Discovery by Calcutta Professor.” Raman submitted a three-paragraph report to Nature on March 8, which was published on April 21. The actual data was sent to the same journal on March 22 and was published on May 5. Raman presented an official and detailed account as “A New Radiation” at the meeting of the South Indian Science Association in Bangalore on March 16. His lecture was published in the Indian Journal of Physics on March 31. On that day, a thousand copies of the reprint were sent to scientists in various countries.
Reception and Impact
Some physicists, especially French and German physicists, initially doubted the validity of the discovery. George Joos at the University of Jena asked Arnold Sommerfeld at the University of Munich, “Do you think Raman’s work on optical Compton effect is reliable?… The sharpness of the scattered lines in liquids makes me skeptical.” Sommerfeld attempted to replicate the experiment, but without success. On June 20, 1928, at the University of Berlin, Peter Pringsheim successfully presented Raman’s results again. He coined the terms “Raman Effect” and “Raman Lines” in his subsequent publications.
Besides being a new phenomenon, the Raman effect was one of the early confirmations of the quantum nature of light. Robert W. Wood at Johns Hopkins University in 1929 was one of the first Americans to confirm the Raman effect experimentally. He commented, “I feel that it is very beautiful that the discovery of Raman effect, after a long and patient study of the phenomena of light scattering, stands as one of the most concrete proofs of quantum theory.” Raman’s spectroscopic work was based on this phenomenon, and Ernest Rutherford, President of the Royal Society, referred to it in his presentation of the Hughes Medal in 1930 as “one of the best three or four discoveries in experimental physics in the last decade.”
Raman believed he would also win the Nobel Prize in Physics, but when the Nobel Prizes were awarded to Owen Richardson in 1928 and to Louis de Broglie in 1929, he was disappointed. He was so confident of winning the prize in 1930 that he booked a ticket, though the announcement was to be made in November. He scanned each day’s newspaper for the announcement and discarded it if it did not contain the news. Finally, he won the prize that year.
Last days of C.V. Raman
At the end of October 1970, Raman suffered a heart attack and collapsed in his laboratory. He was taken to the hospital, where doctors assessed his condition and announced that he would not survive the next four hours. However, he remained alive for a few more days and requested to be surrounded by his followers in the gardens of his institute.
Two days before his death, he said to one of his former students, “Do not let the journals of the academy die, for they are sensitive indicators of the quality of science being done in the country and whether science is taking root or not.” That evening, Raman met with the management board of his institute in his bedroom to discuss the fate of the institute’s administration. He also expressed to his wife the desire for a simple cremation without any rituals upon his death. The next morning, on November 21, 1970, at the age of 82, he passed away due to natural causes.