3. 1923 – Inelastic
light scattering
predicted by A.
Smekel
1928 – Landsberg
and Mandelstam
saw unexpected
frequency shifts in
scattering from
quartz
1928 – C.V. Raman
and K.S. Krishnan
saw “feeble
fluorescence” from
neat solvents
1930 – C.V. Raman
wins Nobel Prize
5. The scattering caused when incident
radiation strikes particles that have
dimensions equal to or greater than
the wavelength of incident radiation.
Tyndall scattered radiations have the
same wavelength as that of incident
radiation.
6. As the wavelength of scattered radiation
is same to that of incident radiation so
this type of scattering is not useful for
qualitative analysis.
Also the scattered radiations is not
characteristic of a particular chemical
substance.
7. The scattering occur when the diameter
of the particles that cause the scattering
are small(5 percent or less of the
wavelength) in comparison to the
wavelength of incident radiation.
The wavelength of both the scattered
and incident radiations are same.
8.
9.
10.
11.
12.
13. The Raman spectroscopy is basically used for
characterization of the research products
1) QUALITATIVE ANALYSIS.
2) QUANTITATIVE ANALYSIS.
14. Raman spectrum
shows that;
Whether the sample is
polarizble or not.
Because Raman
scattering occur
after a dipole is
induced in a
molecule by the
incident radiation .
It also indicates the
presence of
vibrational levels
within the sample.
15.
16. 1):MOLECULAR IDENTIFICATION:
It provide a finger print by which the
molecule can be identified.
e.g SiO ,Si2O2 and Si3O3 were identified by
raman and IR spectra.
17. Being non
destructive and
efficient method
used for
investigation of
work of art.
E.g Identification of
individual pigments
and their
degredation product
leads to insight into
the working method
of artist .
It also gives
information about
the original state of
painting .
18. For instance , they
are used in
medicine for real-
time monitering of
anesthetic and
respiratory gas
mixtures during
surgery.
19. It gives information on the
crystal orientation.
E.g polarization of the raman
scattered light with respect to
the crystal and the polarization
of the laser light can be used to
find the orientation of the
crystal if the crystal structure is
known.
20. Conclusively we can say that it is more
efficient method compare with IR for the
identification of the sample ,concentration
of the sample ,quality of the sample.
