Laser Raman Spectroscopy


 

Laser Raman Spectroscopy

Technique:

Laser Raman spectroscopy depends on a change in the polarization of a molecule to produce Raman scattering. When a beam of photons strikes a molecule, the photons are scattered elastically (Rayleigh scattering) and inelastically (Raman scattering) generating Stoke’s and anti-Stokes lines.

Because Raman spectroscopy is a scattering process, samples of any size or shape can be examined. Very small amounts of material can be studied down to microscopic levels (~1µm).

Instrument:

Renishaw Model 2000 Raman Spectrometer with
Two wavelengths available: 633nm and 514nm

System Accessories:

  • Microscope with Macro Point Accessory Kit, allowing analysis of powders, liquids, and films
  • Global Raman imaging: allows one to quickly image different moieties on a catalyst surface (e.g. changes in oxidation state, crystal form)
  • Raman Mapping Stage: allows one to map discrete areas on a flat surface, collect whole spectra from each area and derive 3D maps from the data
  • Line Focus Accessory: allows one to defocus the Laser beam to cover a discrete line on the surface of the sample and collect maps

Selected Applications in Industry:

  • Differentiation of carbon nanotube species (SWCNT, MWCNT)
  • Identification of corrosion products on various metal surfaces
  • Identification of different forms of carbon (e.g. diamond, graphitic, amorphous, diamond-like, nanotubes)
  • Detection of different inorganic oxides and, in some instances, their crystal form
  • Identification of micron-sized contaminants on photomasks
  • Identification of pigments in some paints and inks