Raman spectroscopy
 
Raman spectroscopy is a spectroscopic technique to study vibrational, rotational, and other low-frequency modes in a system. Since vibrational information is very specific for the chemical bonds in molecules, Raman spectroscopy therefore provides a fingerprint by which the molecule can be identified. The fingerprint region of organic molecules is in the range 500-2000 cm-1.  
 
Raman optical activity spectroscopy. Exploits Raman scattering and optical activity effects to reveal detailed information on chiral centers in molecules.
 
Another way that the technique is used is to study changes in chemical bonding.
 
In solid state physics, spontaneous Raman spectroscopy is used to, among other things, characterize materials, measure temperature, and find the crystallographic orientation of a sample.
 
As with single molecules, a given solid material has characteristic phonon modes that can help an experimenter identify it. In addition, Raman spectroscopy can be used to observe other low frequency excitations of the solid, such as plasmons, magnons, and superconducting gap excitations.
 
The spontaneous Raman signal gives information on the population of a given phonon mode in the ratio between the Stokes (downshifted) intensity and anti-Stokes (upshifted) intensity.
 
Source:
Raman spectroscopy
http://en.wikipedia.org/wiki/Raman_spectroscopy#Applications
 
See also:
Raman effect  
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