C.
V. Raman
Sir
Chandrasekhara Venkata Raman FRS (/rmn/; 7 November 1888 – 21 November 1970)
was an Indian physicist who was most recognised for his work in the field of
light scattering. S. Krishnan noticed that some of the deflected light changes
wavelength and amplitude when it passes through a transparent material. The
Raman effect (Raman scattering) was named after this phenomena, which was a new
sort of light scattering. Raman won the Nobel Prize in Physics in 1930, and was
the first Asian person to win a Nobel Prize in any discipline of science.
Raman, a
precocious youngster born to Tamil Brahmin[6] parents, finished his secondary
and higher secondary schooling at St Aloysius' Anglo-Indian High School at the
ages of 11 and 13, respectively. At the age of 16, he topped the University of
Madras bachelor's degree exams with honours in physics from Presidency College.
While still a graduate student, he published his first research work on light
diffraction in 1906. He earned his M.A. the following year. He joined the
Indian Finance Service in Calcutta as an Assistant Accountant General when he
was 19 years old. He met the Indian Association for the Cultivation of Science
while he was there (IACS), the first research institute in India, where he was able to conduct autonomous
study and make significant discoveries in the fields of acoustics and optics.
Ashutosh
Mukherjee appointed him as the first Palit Professor of Physics at the
Rajabazar Science College of the University of Calcutta in 1917. On his first
trip to Europe, viewing the Mediterranean Sea encouraged him to identify the
dominant explanation for the blue colour of the sea at the time, namely the
reflected Rayleigh-scattered light from the sky, as being wrong. In 1926, he
started the Indian Journal of Physics. On February 28, 1928, he and Krishnan
discovered a novel light scattering phenomena named "modified
scattering," but better known as the Raman effect. Every year, the Indian
government commemorates the day as National Science Day. In 1933, Raman became the first Indian
Director of the Indian Institute of Science in Bangalore. In the same year, he
established the Indian Academy of Sciences. In 1948, he founded the Raman
Research Institute, where he worked until his death.
In 1954,
India's government bestowed the first Bharat Ratna, the country's highest
civilian honour.
Later, in
protest of Prime Minister Jawaharlal Nehru's stance on scientific research, he
destroyed the medallion.
Early childhood
development and education
C. V. Raman
was born in Tiruchirapalli, Madras Presidency (now Trichy, Tamil Nadu), to
Hindu Tamil Brahmin parents Chandrasekhara Ramanathan Iyer and Parvathi Ammal.
He was the second of eight siblings. His family relocated to Visakhapatnam
(formerly Vishakapatnam or Vizagapatam or Vizag) in Andhra Pradesh in 1892 when
his father was recruited to the faculty of physics at Mrs A.V. Narasimha Rao
College.
Raman
attended St Aloysius' Anglo-Indian High School there. He passed matriculation
at age 11 and the FA examination (similar to today's Intermediate exam, PUCPDC
and +2) with a scholarship at age 13,securing first rank in both under the
Andhra Pradesh school board examination.
Raman
enrolled at Presidency College in Madras (now Chennai) in 1902, where his
father had been moved to teach mathematics and physics.19 At the age of 18, he
received a bachelor's degree from the University of Madras, where he placed
first and won the gold medal in physics and English. In 1906, while still a graduate
student, he published his first scientific publication in the British magazine
Philosophical Magazine, titled "Unsymmetrical diffraction bands due to a
rectangular aperture." [20] In 1907, he earned a master's degree with
honours from the same university. Surface tension of liquids was the subject of
his second work published in the same journal that year. It was alongside Lord Rayleigh's study on the
sensitivity of the ear to sound,that Lord Rayleigh began to communicate with
Raman, calling him courteously as "Professor." Richard Llewellyn Jones, Raman's
physics teacher, was well aware of his abilities and insisted that he continue
his research in England. Jones arranged for Raman's physical inspection with
Colonel (Sir Gerald) Giffard. The inspection revealed that Raman would not
withstand the harsh weathers of England,he incident of which he later recalled,
and said, "[Giffard] examined me and certified that I was going to die of
tuberculosis… if I were to go to England."
Career
Chandrasekhara
Subrahmanya Ayyar, Raman's older brother, had entered the Indian Finance
Service (now Indian Audit and Accounts Service), India's most prominent
government service. [The most sought service, the Indian Civil Service (ICS),
was recruited in England at the time. Raman, unable to study overseas, followed
suit and qualified for the Indian Finance Service in February 1907, taking
first place in the entrance examination. " In June 1907, he was assigned
to the Indian Association for the Cultivation of Science in Calcutta (now
Kolkata) as Assistant Accountant General (IACS), He quickly contacted Asutosh Dey, who would later
become his lifelong partners, Amrita Lal Sircar, the institute's founder and
secretary, and Ashutosh Mukherjee, the institute's executive member and Vice
Chancellor of the University of Calcutta. With such a connection, he was able
to conduct research on his own time, even "at very unusual hours," as
Raman later reminisced. The institute had not yet recruited regular researchers
or published any research papers.Raman's article "Newton's rings in
polarised light" was published in Nature in 1907. .
In 1909, the
Indian Association for the Cultivation of Science (IACS) published a
publication called Bulletin of Indian Association for the Cultivation of
Science, in which Raman was a key contributor
In 1909,
Raman was transferred to Rangoon, British Burma (now Myanmar), to take up the
position of currency officer. He had to return to Madras after only a few
months since his father died of a terrible disease. He stayed in Rangoon for
the rest of the year due to his father's death and burial rituals. In 1910, he
was relocated to Nagpur, Maharashtra.[31] Even before he had served for a year
in Nagpur, he was elevated to Accountant General in 1911 and sent back to
Calcutta.
The
University of Calcutta began assigning research scholars to Raman at IACS in
1915. Sudhangsu Kumar Banerji, a PhD student under Ganesh Prasad (who later
became Director General of Observatories of India Meteorological Department),
was his first student. University of Allahabad, Rangoon University, Queen's
College Indore, Institute of Science, Nagpur, Krisnath College, and University
of Madras all followed suit the next year. Raman had mentored almost a dozen
students by 1919. Raman obtained two honorary appointments at IACS after
Sircar's death in 1919: Honorary Professor and Honorary Secretary. He referred to this time in his life
as his "golden era."
Raman was
appointed Palit Professor of Physics at the University of Calcutta in 1913, a
position named after the donor Sir Taraknath Palit. The appointment was made by
the university senate on January 30, 1914, as reported in the meeting minutes:
At the
Senate meeting on January 30, 1914, the following appointments to the Palit
Professorships were made: Dr P C Ray and Mr C.V. Raman, MA... Each Professor's
position will be indefinite. When a professor reaches the age of sixty, he must
resign from his position. Ashutosh Mukherjee had invited Jagadish Chandra Bose
to take over the role prior to 1914, but Bose had declined. When a second choice,
Raman became the first Palit Professor of Physics but was delayed for taking up
the position as World War I broke out. He did not become a full-fledged
professor until 1917, when he joined Rajabazar Science College, a campus
established by the University of Calcutta in 1914. After a decade of
service, he unwillingly left as a civil servant, which he regarded as
"supreme sacrifice. since
his salary as a professor would be roughly half of his salary at the time. But
the advantage was the terms and conditions were congenial to him, as plainly
expressed in the report of his joining the university, which stated:
Acceptance
of the Sir T N Palit Professorship by Mr C.V. Raman on the proviso that he not
be obliged to go outside of India... Mr. C. V. Raman began his employment as
Palit Professor of Physics on 2.7.17, according to reports... Mr Raman has been
advised that he will not be obliged to teach MA and MSc sessions, which will
allow him to focus on his own research or aid advanced students with their studies.
Some members
of the University of Calcutta Senate, particularly foreign members, were
outraged by Raman's nomination as the Palit Professor because he lacked a PhD
and had never studied abroad. As a sort of response, Mukherjee arranged for
Raman to get an honorary DSc from the University of Calcutta in 1921. In the
same year, he went to Oxford to give a talk at the British Empire's Congress of
Universities. His hosts were J. J. Thomson and Lord Rutherford, and he was
well-known at the time. When Mukherjee asked him about his future goals
after he was elected as a Fellow of the Royal Society in 1924, he said, "Of
course, the Nobel Prize." As the first editor of the Indian Journal of
Physics, he founded the journal in 1926. In the second volume, he published his
renowned essay "A new radiation," which reported the discovery of the
Raman effect.
In 1932,
Raman was succeeded as Palit Professor by Debendra Mohan Bose. In 1933, he left
Kolkata to become the first Indian director of the Indian Institute of Science
in Bangalore. The lands and funds for the Indian Institute of Science in
Bangalore were donated by Maharaja Krishnaraja Wadiyar IV, the King of Mysore,
Jamsetji Tata, and Nawab Sir Mir Osman Ali Khan, the Nizam of Hyderabad. In
1909, the Viceroy of India, Lord Minto, approved the formation, and Morris
Travers was nominated as the first Director by the British government. The
fourth Director was Raman. He recruited G. during his time at IISc. N.
Ramachandran, who eventually rose to prominence as an X-ray crystallographer.
He formed the Indian Academy of
Sciences in 1934 and started publishing the proceedings of the academy. Around that time, the Calcutta Physical
Society was founded, with Raman spearheading the idea in early 1917. In 1943,
Raman founded Travancore Chemical and Manufacturing Co. Ltd. with his old
student Panchapakesa Krishnamurti. The
company was one of the first organic and inorganic chemical manufacturers, and
was renamed TCM Limited in 1996. Raman was named the first National
Professor of Independent India by the new government in 1947.
In 1948,
Raman left the Indian Institute of Science and founded the Raman Research
Institute in Bangalore the next year. He was the organization's director, and
he stayed involved until his death in 1970.
Contributions
to science
The states
involved in the Raman signal are depicted in an energy level diagram.
From left,
C. Raman, Raman, Raman, Raman, Raman, Raman, Raman, Raman, Raman, Raman, Raman,
Raman, Sinclair Lewis (physics), V. Raman (chemistry), Hans Fischer
(chemistry), Karl Landsteiner (medical), and V. Raman (literature)
The sound
of music
Understanding
the physics of musical sounds was one of Raman's passions. Between 1916 and
1921, he was motivated by Hermann von Helmholtz's The Sensations of Tone, a
book he came across when he joined IACS.He explored and published his
discoveries in a prolific manner. On the basis of superposition of velocities,
he developed the theory of transverse vibration of bowed string instruments.
He researched the acoustics of
many violin and related instruments, including Indian stringed
instruments, and water splashes, and even performed
"Experiments with mechanically-played violins."
Raman also
researched the distinctiveness of Indian drums. His analysis of the harmonic
nature of the sound of the tabla and mridangam were the first scientific studies
on Indian percussion. He produced a critical inquiry on Kaufmann's hypothesis
on pianoforte string vibrations. He was able to investigate how sound travels through the
Whispering Gallery of St Paul's Cathedral's dome, which produces strange sound
effects. His work on acoustics was a crucial forerunner, both
empirically and philosophically, to his subsequent works on optics and quantum
physics.
The sea's
colour is blue.
Raman began
investigating light scattering in 1919, as part of his wider excursion into
optics. His first astonishing physics finding was the blue colour of
seawater. During a trip back to the United States on the S.S. In September
1921, Narkunda reflected on the Mediterranean Sea's blue hue. He researched
seawater using rudimentary optical equipment, a pocket-sized spectroscope, and
a Nicol prism in hand.Of various speculations on the colour of the
sea,Lord Rayleigh's in 1910 was the best. "The much-admired dark blue of
the deep sea has nothing to do with the colour of water, but is merely the blue
of the sky viewed through reflection," according to the author. Rayleigh had correctly explained the nature of the blue sky using a process
known as Rayleigh scattering, which is the scattering and refraction of light
by particles in the atmosphere. Raman could see the water via the Nicol
prism without being affected by sunlight reflected off the surface. In contrast
to Rayleigh, he noted how the sea appeared even bluer than usual. As soon as
the S.S. arrives, While the Narkunda was parked in Bombay Harbour, Raman
completed an article titled "The Color of the Sea," which was
published in Nature in November 1921. Rayleigh's answer, he thought, is "questionable
by a simple mode of observation" (using the Nicol prism).
Looking down
into the water with a Nicol in front of the eye to eliminate off surface
reflections, the sun's rays might be seen entering the water and appearing to
converge to a point at a significant depth inside it due to perspective. What
is it, exactly, that diffracts light and makes its passage visible? The diffracting particles could, at
least in part, be the water molecules themselves, which is an intriguing notion
to examine in this context .
When he
reached Calcutta, he asked his student K.R. Ramanathan, a researcher from the
University of Rangoon, came to the following conclusion in early 1922, as
recorded in the Proceedings of the Royal Society of London:
In this
study, it is recommended to advocate for a completely different viewpoint,
namely that molecular diffraction controls the apparent luminosity and, to a
large extent, its colour in this occurrence, just as it does in the case of sky
colour. A theoretical calculation and experimental observations of the
intensity of molecule scattering in water will be provided as a required
prelude to the discussion .
Ramanathan
followed up with an elaborate experimental finding in 1923.A subsequent
study in the Bay of Bengal in 1924 provided the conclusive evidence.Water's intrinsic colour is now primarily attributed to the selective
absorption of longer wavelengths of light. Due to harmonics of the infrared absorption O-H stretching
modes of water molecules, in the red and orange portions of the spectrum.
