|
|
|
The
dipole moment oscillates with frequency components
_
|
Rayleigh scattering of unchanged
wavenumber .
|
| _(
- 2')
|
Stokes scattering with decreased
frequency. |
| _(
+ 2')
|
Anti-Stokes scattering with
increased frequency. |
These three terms represent
scattering of the radiation.
Selection Rules for Rotational Raman
It is important to notice that if rotation in the electric field
does not alter the polarisibily
then 
= 0 and the dipole oscillates at the frequency of the incident
radiation i.e. there is no Raman scattering.
Gross Selection Rule for Rotational Raman spectroscopy
The molecule must have an anisotropic polarisibility. |
|
