Why we use Raman spectroscopy

Advantages of Raman spectroscopy

Chemical composition and structure of materials
Raman spectroscopy can differentiate chemical structures, even if they contain the same atoms in different arrangements.

Non-contacting and non-destructive
Analyse your sample multiple times without damage.

Typically no sample preparation
If you can use an optical microscope to focus onto the analysis region, you can use a Raman microscope to collect its Raman spectrum.

You can choose how much, or little, of the sample you want to analyse
The best Raman microscopes provide flexibility in controlling collection volumes, ranging from minute amounts of material (<1 µm in size) to samples centimetres across.

Analyse through transparent containers and windows
Most Raman analyses use visible or near-visible light. It is, therefore, simple to collect the content-rich information even when the sample is sealed within a transparent container (e.g. vial or capillary tube), or within a cell with a viewing window (e.g. temperature or pressure cell).

Sensitive to small changes in material structure
Raman bands result directly from molecular vibrations. These vibrations are very sensitive to changes in chemistry and structure, so you can spot subtle differences in molecular environment. The direct relationship between vibrations and Raman bands also makes interpretation easier.

You can analyse samples in water
You can analyse samples in aqueous solutions, such as suspensions or biological samples. There is no need for time-consuming extraction or drying, which may also alter the chemistry of your samples.

It works on almost all materials
Almost all materials exhibit Raman scattering. The only exception is pure metals, which just reflect light. (However metallurgists use Raman spectroscopy because carbides, nitrides and oxides do Raman scatter).

It uses light
Scientists and engineers can apply the tricks they already know about manipulating light to Raman spectroscopy. For example:

• fitting a powerful microscope to a Raman spectrometer enables the analysis of micrometre-sized particles of material.
• fibre optics can be used to make Raman measurements remote from the Raman system. This is perfect for applications where very large samples need analysing, or where remote in situ measurements are needed (such as when Raman analyses are being undertaken on a synchrotron beamline or in a process reactor).

Other benefits:

• High resolution Raman systems reveal numerous well-defined Raman bands, enabling not only unambiguous material identification but also the determination of sample stress.

Getting the best from your Raman system

While Raman spectroscopy has many advantages, it can present some challenges. Find out about the ways we can address some of the issues encountered during its use.