Raman Spectrometry (Raman)

Raman Spectrometry (Raman)

Raman Spectroscopy is a vibrational spectroscopic technique that uses the wavelength shift of light scattered (Raman shift) from molecules in a sample, to characterize them. When light of known wavelength is inelastically scattered by matter, the wavelength shift (or frequency shift) of the scattered photons is different from the incident photons. The shift is related to the molecular vibrations, which are unique to each molecular structure. The change in frequency of scattered photons may be positive or negative. Raman spectroscopy involves detecting and recording these wavelength shifts and using them to analyze what is in the sample. A Raman spectrum will have several peaks, each peak corresponding to a specific mode of molecular vibration of a chemical species. The position of the peaks is used for species identification, while its intensity indicates species concentration. Several variations of the basic technique exist, such as Resonance Raman, Spontaneous Raman, Fourier Transform Raman, Surface Enhanced Raman Spectroscopy, and nonlinear coherent Raman techniques, such as hyper Raman spectroscopy. The types of materials to which Raman Spectroscopy can be applied is wide ranging, including dissolved organic and inorganic molecules, crystalline solids, ceramics, glasses, nanostructure materials and microorganisms. In the case of gases, the concentration of molecules in a gas is typically very low, so special measurement techniques to enhance the signals are needed.

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Common Uses of Raman Spectrometry (Raman) 

• Water pollution monitoring
• Coal and derivatives analysis
• Characterization of 2D materials like Graphene
• Characterization of crystal structures
• Biochemical studies at cellular level
• Medical research such as study of transdermal delivery of drugs into skin

Advantages of Raman Spectrometry (Raman) 

• Non-destructive technique
• Small sample quantity with minimal preparation
• Rapid analysis
• Applicable for wide range of organic and inorganic materials

Limitations of Raman Spectrometry (Raman) 

• Many compounds are not suitable for Raman spectrometry due to molecular asymmetry or fluorescent effects
• Cannot be used for metals and alloys

Industrial Applications of Raman Spectrometry (Raman) 

• Chemical and molecular analysis
• Biological research
• Materials testing and characterisation
• Environmental analysis
• Medical research
• Pharmaceutical research and quality control