Raman spectroscopy is a spectroscopic technique used to study vibrational, rotational, and other low-frequency modes in a system. It involves scattering of monochromatic light, such as visible light, from a sample. Most of the scattered light is of the same wavelength as the incident light (Rayleigh scattering). However, a small fraction of the light gets scattered at wavelengths different from the incident wavelength (Raman scattering). Raman scattering that results in wavelengths longer than the incident wavelength is called Stokes radiation, while scattering at shorter wavelengths is called anti-Stokes radiation. Raman spectroscopy utilizes the Raman scattering effect to obtain a molecular fingerprint spectrum for identification of molecules.

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E.M.G. YADAVA WOMEN’S COLLEGE, MADURAI – 625 014.
(An Autonomous Institution – Affiliated to Madurai Kamaraj University)
Re-accredited (3rd Cycle) with Grade A+ and CGPA 3.51 by NAAC
TOPIC: Raman spectroscopy
By
Mrs. P.Revathi,
Department of physics,

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Raman spectroscopy
• Scattering of light
• Rayleigh Scattering
• Raman Scattering
• Stokes and antistokes Radiation
• Raman spectroscopy

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Scattering of light
 When a monochromatic beam of visible light passes through a
Non-absorbing medium, part of the light scattered and a small
part transmitted

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Rayleigh scattering
Most of the scattering light Will have the same frequency as the
incident frequency is called Rayleigh scattering.
Examples: The sky is blue due to scattering of light by atmospheric
particles.

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Raman scattering
In addition certain discrete frequencies above and below that of the
incident beam Will be scattered. This is known as Raman
scattering.

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Stokes and Antistokes radiation
 Radiation scattered with a frequency lower than that of the
incident beam is called Stokes radiation.
 Radiation scattered with a frequency higher than that of the
incident beam is called antistokes radiation.

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Raman spectroscopy
 The spectral method developed by the Raman scattering or
Raman effect is known as Raman spectroscopy.
 This spectroscopic technique is used in condensed matter to
study about vibrational, rotational And other low frequency mode
in a system.

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References
 Barnwell C. N.Mc.cash.E.M, Fundamentals of Molecular Spectroscopy ,
Tata McGraw-Hill, New Delhi, fourth edition, 2011.
 P.S.Sindhu, Fundamentals of Molecular Spectroscopy, New age
International Publishers, second edition, January 2011.
 N.H.Colthup, L. H. Daly, S. E. Wimberley Introduction to Infrared and
Raman Spectroscopy, Third edition.
 Smith & G. Dent, Modern Raman Spectroscopy: A Practical Approach 1st
ed. , Wiley (2005)

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Thank you