What information does Raman spectroscopy provide ?

Raman spectroscopy probes the chemical structure of a material and provides information about:

  • Chemical structure and identity
  • Phase and polymorphism
  • Intrinsic stress/strain
  • Contamination and impurity

Typically a Raman spectrum is a distinct chemical fingerprint for a particular molecule or material, and can be used to very quickly identify the material, or distinguish it from others.  Raman spectral libraries are often used for identification of a material based on its Raman spectrum – libraries containing thousands of Raman spectra are rapidly searched to find a match with the spectrum of the analyte.

Raman spectra of ethanol and methanol, showing the significant spectral differences which allow the two liquids to be distinguished.
Raman spectra of ethanol and methanol, showing the significant spectral differences which allow the two liquids to be distinguished.

In combination with mapping (or imaging) Raman spectrometer, it is possible to generate images based on the sample’s Raman spectra.  These images show distribution of individual chemical components, polymorphs and phases, and variation in crystallinity.

Raman spectral image of a whole pharmaceutical tablet, showing the distribution of aspirin (red), caffeine (green) and paracetamol (blue).
Raman spectral image of a whole pharmaceutical tablet, showing the distribution of aspirin (red), caffeine (green) and paracetamol (blue).
How does Raman Spectroscopy work - FAQs