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D. K. Pandey et al.
to do with that, it is just the reflection of the sky. After astonishing about the blue
color of deep seawater, onboard Raman carried out few experiments of viewing the
surface of seawater through Brewsterian angle and observed that the blue color of
deep seawater is far from the reflection of the sky and depicts that the phenomena
have nothing related to the reflection of the sky. After his return, Raman immediately
started the series of experiments on the scattering of light at the Indian Association
for the Cultivation of Science (IACS), Calcutta, India. During this period (at least
6 years) Raman and his brilliant students have published almost 56 research papers in
various prestigious scientific journals and proceedings on different laws of molecular
scattering for the structure of molecules, pressure and temperature-dependent phase
transition, etc. [1]. During the experiments of scattering phenomena, Sir Raman
and his students obtained the frequency shift after the scattering of the incident light.
However, this observation is not in agreement with the Rayleigh scattering, therefore,
they assumed that the shift in frequency may be due to the fluorescence. To get rid of
this, they purified the samples too many times and performed the same experiments,
nevertheless they obtained the frequency shift, which leads to the belief that the
fluorescence is not present. Therefore, Raman told his student, K. S. Krishnan to
focus only on the undefined scattering in the liquids. For this experiment, the source
of light is the sunlight which was focused by telescope objective lens and shortfocus lens. Then the light was passed through the blue-violet filter and incident on
the flask, which contained the liquid sample. When the secondary green filter was
along the incident beam, scattered light was not observed in the transverse direction.
However, when they used the mercury bulb instead of sunlight, the opalescent of the
track of scattered light observed for over 80 liquids and gas samples and all shows
ubiquitous nature phenomena. Further, it was different from the fluorescence and
exhibits strong polarization same as the unmodified scattered light. They named the
effect as ‘modified scattering’ and realize that the phenomenon is a new fundamental
observation. Then after Raman communicated the letter to Nature journal entitled
“A new type of secondary radiation” in February 1928 [2]. In the notes of K. S.
Krishnan, an interesting point is noted that modified radiation is originated from
the molecular vibrations from the normal state. Further, Raman and his student
started to understand the effect of the incident light having a different wavelength.
In that experiment, they surprisingly observed the modified scattering was distinct
from the incident unmodified light. These results were further sent to the Nature
journal for the publication and after the rejection of the referee, the editor Sir Richard
Gregory has taken a responsibility for the publication. In that paper, Sir Raman and his
students have determined that incident lines generate its modified line having strong
polarizability. Further, they also acquired that most of the modified lines consisting
of the lower frequency than that of the incident one, while few shows the higher than
the incident. Such frequency lines were observed for almost all the type of matters
such as liquids, gases, crystalline materials as well as the optical glasses, which
indicates the universal behavior of the phenomenon. Instead of relying on the costly
equipment, the fine and final form of the discovery of modified scattering depends
on the caliber of the scientists. For such great achievement, Professor Raman was
awarded the Noble Prize for physics in the year of 1930.
D. K. Pandey et al.
to do with that, it is just the reflection of the sky. After astonishing about the blue
color of deep seawater, onboard Raman carried out few experiments of viewing the
surface of seawater through Brewsterian angle and observed that the blue color of
deep seawater is far from the reflection of the sky and depicts that the phenomena
have nothing related to the reflection of the sky. After his return, Raman immediately
started the series of experiments on the scattering of light at the Indian Association
for the Cultivation of Science (IACS), Calcutta, India. During this period (at least
6 years) Raman and his brilliant students have published almost 56 research papers in
various prestigious scientific journals and proceedings on different laws of molecular
scattering for the structure of molecules, pressure and temperature-dependent phase
transition, etc. [1]. During the experiments of scattering phenomena, Sir Raman
and his students obtained the frequency shift after the scattering of the incident light.
However, this observation is not in agreement with the Rayleigh scattering, therefore,
they assumed that the shift in frequency may be due to the fluorescence. To get rid of
this, they purified the samples too many times and performed the same experiments,
nevertheless they obtained the frequency shift, which leads to the belief that the
fluorescence is not present. Therefore, Raman told his student, K. S. Krishnan to
focus only on the undefined scattering in the liquids. For this experiment, the source
of light is the sunlight which was focused by telescope objective lens and shortfocus lens. Then the light was passed through the blue-violet filter and incident on
the flask, which contained the liquid sample. When the secondary green filter was
along the incident beam, scattered light was not observed in the transverse direction.
However, when they used the mercury bulb instead of sunlight, the opalescent of the
track of scattered light observed for over 80 liquids and gas samples and all shows
ubiquitous nature phenomena. Further, it was different from the fluorescence and
exhibits strong polarization same as the unmodified scattered light. They named the
effect as ‘modified scattering’ and realize that the phenomenon is a new fundamental
observation. Then after Raman communicated the letter to Nature journal entitled
“A new type of secondary radiation” in February 1928 [2]. In the notes of K. S.
Krishnan, an interesting point is noted that modified radiation is originated from
the molecular vibrations from the normal state. Further, Raman and his student
started to understand the effect of the incident light having a different wavelength.
In that experiment, they surprisingly observed the modified scattering was distinct
from the incident unmodified light. These results were further sent to the Nature
journal for the publication and after the rejection of the referee, the editor Sir Richard
Gregory has taken a responsibility for the publication. In that paper, Sir Raman and his
students have determined that incident lines generate its modified line having strong
polarizability. Further, they also acquired that most of the modified lines consisting
of the lower frequency than that of the incident one, while few shows the higher than
the incident. Such frequency lines were observed for almost all the type of matters
such as liquids, gases, crystalline materials as well as the optical glasses, which
indicates the universal behavior of the phenomenon. Instead of relying on the costly
equipment, the fine and final form of the discovery of modified scattering depends
on the caliber of the scientists. For such great achievement, Professor Raman was
awarded the Noble Prize for physics in the year of 1930.