Advantages Of Raman Spectroscopy

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Raman spectroscopy utilises inelastic scattering of monochromatic light to generate Raman spectra which provides useful information pertaining to crystal structures. In this technique, laser light is utilized as a source to irradiate the sample. Photons of the laser light are absorbed by the sample and then re-emitted. The frequency of the re-emitted photons either gets increased or decreased in comparison to the original monochromatic frequency, which is termed as Raman effect. This shift provides information about vibrational, rotational and other low frequency transitions in molecules. Raman spectroscopy can be used to probe solid, liquid and gaseous samples. The characteristic fingerprinting pattern in a Raman spectrum enables identification…show more content…
When light is scattered by matter in such a manner that there is no change in the energy in the scattered wave (elastic), the scattering is termed as Rayleigh scattering. When the scattering is inelastic, thereby resulting into a scattered light with different energy from incident light, the scattering is referred to as Raman scattering. The aforesaid phenomenon was experimentally observed for the first time by Chandrasekhara Venkata Raman in 1928 and came to be known as Raman…show more content…
The ratio of Stokes Raman and anti-Stokes Raman scattering depends on the population of the various states of the molecule. At room temperature, the number of molecules in an excited vibrational level is smaller than that of in the ground level due to which the intensity of the Stokes Raman light is typically higher than anti-Stokes Raman light. In standard Raman measurement, Rayleigh scattered light is filtered out and only the Stokes Raman scattering is recorded for simplicity. The intensity of anti-Stokes Raman light rises relative to Stokes scattering as the temperature escalates, thus the intensity ratio of anti-Stokes and Stokes light can be used to calculate the temperature of a sample. The Raman spectrum is expressed in a form of intensity of scattered light versus wavenumber. Wave number is reciprocal of wavelength and is called Raman

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