ABSTRACT
The Raman effect is particularly useful for characterizing vibrations centered in highly polarizable bonds (involving either hetero- or homo-atoms), whereas infrared excites vibrations centered in polarized bonds (involving heteroatoms). In general, selection rules for the Raman effect are somewhat more liberal than those for infrared absorption. The well-known principle of mutual exclusion states that when a molecule contains a center of symmetry, those vibrations that are infrared active will not be Raman active and vice versa. Symmetric vibrations give rise to intense Raman bonds, while antisymmetric vibrations are generally weaker.
