Degenerate vibrations Coriolis splitting

The Coriolis interaction is found to be larger for degenerate vibrational states than for nondegenerate levels. Thus, for symmetric rotor molecules, the doubly degenerate vibrations may be split so that they differ slightly in energy. The fine-line structure of the absorption band will then show lines due to transitions to both of these levels. For spherical rotor molecules, the Coriolis interaction will cause the triply degenerate frequencies to split. 

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