1. Sir C V RAMAN
C V Raman is one of
the most renowned scientists
produced by India. His full names
was Chandrashekhara Venkitta
Raman. For his pioneering work
of scattering of light, C V Raman
won the nobel prize for physics
in 1930. Chandrashekhara
Venkitta Raman was born on
November 07, 1888 in
Thiruchinapally, Thamilnadhu.
He was the second child of
Chandrashekhar Iyer and
parvathyamma. His father was
lecturer in Mathematics and Physics, so he had an academic
atmosphere at home. He entered presidency college, in Madras, 1902
and in 1904 passed his BA Examination, winning the first place and the
gold medel in physics in 1907 C V Raman passed his MA obtaing the
highest distinctions. During those time there were not many
opportunity for scientist in India therefore Raman joined the Indian
Finance Department in 1907. After his office hours he carried out his
experimental research in the laboratory of Indian Association for the
cultivation of science at Calcutta. He carried out research in acoustics
and optics.
2. In 1917 Raman was offered the position of sir Taraknath Palit
Professorship of Physics at Culcatta University. He stayed therefore the
next 15 years. During his tenure there, he received world wide
recognition for his work in optics and scattering of light he was elected
the royal society of London in 1924 and the British mande him a knight
of British Empire in 1929. In 1930 Sir C V Raman was awarded with
nobel prize in physics for his work on scattering of light. The discovery
was later christened as “Raman Effect”.
In 1934 C V Raman become the director of the newly
established Indian Institute of Sciences in Bangalore, where two years
later he continued as a professor of Physics. Other investigation carried
out by Raman: his experimental and theoretical studies on the
diffraction of light by Acoustics 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 1947 he was
appointed as the first national professor by the new government of
independent India. He retried from the Indian Institute in 1948 and a
year later he established the Raman research Institute in Bangalore,
where he worked till his death
3. Raman Effect
Raman Effect, change in wavelength of light that occurs
when a light beam is deflected by molecules. When a beam of light
traverses a dust free, transparent sample of a chemical compound, a
small fraction of the light emerges in directions other than that of the
incident beam. Most of this scattered light is of unchanged wavelength.
A small part however has wavelengths different from that of incident
light; its presence is a result of Raman Effect.
The phenomenon is named for Indian physicist C V
Raman. Who first published observations of the effect in 1928. Raman
scattering is perhaps most easily understandable if the incident light is
considered as consisting particles or photons, that strike the molecules
of the sample. Most of the encounters are elastic, and the photons are
scattered with unchanged energy and frequency. On some occasion
however the molecule takes up energy from or gives up energy to the
photons, which are there by scattered with diminished or increased
energy, hence with lower or higher frequency. The frequency shift are
thus measure of the amount of energy involved in the transition
between initial and final states of the scattering molecules
4. The Raman is feeble; for a liquid compound the intensity of the
affected light may be only 1/100000 of that incident beam. The pattern
of the Raman lines is characteristic of the particular molecular species,
and its intensity is proportional to the number of scattering molecule in
the path of light. Thus Raman Spectra is used in qualitative and
quantitative analysis.
The energies corresponding to the Raman frequency shifts are
found to be the energies associated with transitions between differed
rotational and vibrational states of the scattering molecules. In liquids
rotational motions are hindered, and discrete rotational Raman lines
are not found. Most Raman work is concerned with vibrational
transitions, which give larger shifts observable for gases liquid and
solids. Gases have low molecular concentration at ordinary pressures
and therefore produce very faint Raman Effect; thus liquid and solid are
frequently studied.
