Question

Even though water molecule vibration is raman active why it is weak raman scatterer

Answer 1

Explanation:

Raman spectroscopy occurs as a result of a molecular vibration causing a "change in polarizability" of the molecule. In contrast, for a molecule to be infrared active, the vibration must cause a change in the permanent dipole moment. A simple case of a Raman Active molecule would be a species such as CS2.