25-08-2017, 09:32 PM
Raman Spectroscopy
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What is Spectroscopy
The study of how 'species' (i.e., atoms, molecules, solutions) react to light. The electromagnetic radiation absorbed, emitted or scattered by the molecule is analyzed. Typically, a beam of radiation from a source such as a laser is passed through a sample, and the radiation exiting the sample is measured. Some, like Raman, depend on a molecule's vibrations in reaction to the light.
Excitation of Raman Spectra
A Raman spectrum can be obtained by irradiating a sample with an intense beam of laser.
The emitted radiation is of two types:
1. Stokes scattering
2. Anti-stokes scattering
3. Rayleigh scattering
Instrumentation of Raman
There are five basic components of a Raman spectrometer
An intense laser source
Sample handling unit
Monochromator or interferometer
Detector
Signal processing and output
device
Application of Raman Spectroscopy
Forensic science/drugs detection
Identification of unknown drugs, fingerprint detection, early
detection of cancers
Non-destructive Analysis of Art objects and heritage
Raman spectroscopy is being used to uncover the secrets of ancient art object. They determine the composition and origins of the paint, paper, inks and pigments used, which will tell them about techniques used and the age of the art objects and heritage.