MOST OUTSTANDING APPLICATIONS OF RAMAN SPECTROSCOPY

    Raman spectroscopy is named after its discoverer ‘Sir Chandrasekhara Venkata Raman’, the great Indian physicist who discovered it in the year 1928. Later on, Sir C.V. Raman received the most prestigious award, the Nobel prize in Physics in the year 1930 for his great discovery of Raman effect. In fact, Sir C.V. Raman was the first Asian to be awarded a Nobel Prize in all fields of science “for his work on the scattering of light and for the discovery of the Raman effect named after him in 1930.” He was the second Indian Nobel Laureate but the first Indian scientist to win Nobel prize. Raman spectroscopy is a Chemical analysis technique that provides detailed information about the molecular structure without causing any physical and chemical changes. It studies the vibrational modes along with translational and rotational modes of the molecule.

    Raman spectroscopy works on the principle of Raman scattering. When a monochromatic radiation incident on the sample, the radiation gets reflected, absorbed, or scattered. The scattered light photons have a different frequency from the incident photon because of the change in the vibrational and rotational properties of the molecules, which results in the change of wavelength of the incident and the scattered light. This change in the frequencies of the incident photon and the scattered photon is known as the Raman shift. When the scattered photon has less energy, hence a longer wavelength than the incident photon, it is called Stokes scattering. When the scattered photon has more energy, hence a shorter wavelength than the incident photon, it is called anti-stokes scattering. 

    The phenomenon of Raman Spectroscopy includes the interaction of light with the chemical bonds inside the molecule. When a high-intensity beam of light falls on the molecule, then it gets scattered in different directions. Most of the scattered light is of the same wavelength as that of the incident light, this is called Rayleigh scattering. Some amount of light is scattered at different wavelengths, this is called Raman scattering. Rayleigh scattering does not provide any information, but Raman scattering provides the Raman spectrum that consists of a number of peaks that represent the intensity and wavelength position of the Raman scattered light. Each peak shows the specific vibrational energy associated with the chemical bonds in a molecule. In this way, Raman spectroscopy helps to interpret the chemical structure of a molecule and its used in many various fields with very wide range of applications as mentioned below for both qualitative and quantitative research and analyses of the molecule because it provides information very easily and rapidly. 

• It is widely applied in life sciences for identification and classification of cells, biosensing, stem cell analysis, to diagnose diseases, monitoring the contents of proteins, lipids and nucleic acid, Single cell analysis, etc.,
• Raman spectroscopy is used in the field of art and archeological findings, even about study of pigment characterization, detailed study of ceramics and gemstones, paintings, dyes and binders, chemical reaction monitoring, identifying molecular structure, identification of minerals and their phase identification, etc., 
• Used in structural analysis of microelectronics, to identify the contamination of semiconductors and their heterostructure characterization, for analysis of intrinsic stress or strain of the molecular structure, to study the photoluminescence imaging of semiconductors.
• For examining the carbon allotropes, to collect spectra of carbon nanotubes, to detect the structural morphology of carbon nanomaterials,
• Used in pharmaceutical and cosmetics industry to determine the distribution of Active pharmaceutical ingredient (API), used for analytical analysis of early drug development, for checking the content uniformity of medicines, for analysis of cosmetic product's permeability, its a very important tool of Process Analytical Technology (PAT) in pharma industries, finally Raman spectroscopy is widely used for quality control of final product of medicines.
• The technique of Raman spectroscopy is effectively used by police and various surveillance agencies like Airports and Seaports security personnel and border security forces to check the illegal moment of banned substances illicit drugs and narcotics as Raman spectra can easily distinguish between two similar-looking white powders, which might look exactly the same to the human eye.

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