Raman Spectroscopy
A vibrational technique based on the small shift in frequency of light scattered inelastically by molecules.
Formula / equation
Δν̃ = ν̃_incident − ν̃_scattered
Unit
cm⁻¹
In depth
Raman activity requires a change in polarisability rather than in dipole moment, so it complements infrared: symmetric vibrations that are infrared-inactive are often strongly Raman-active. Water scatters weakly, which makes Raman especially useful for aqueous and biological samples.
Examples in the real world
Identifying the symmetric C=C stretch in a symmetrical alkene; non-destructive analysis of pigments in paintings.