I have a doubt about the vibrational modes...
If I have a centrosymmetric molecule can I have a vibrational mode that is not active both in RAMAN and IR??
Because I know that for centrosymmetric molecules If a normal mode is active in IR shouldn't be in raman (and vicevresa)
But if I discover for a centrosymmetric molecule that a certain vibrational mode isn't IR actvie can i say aoutomatically that that mode is active in RAMAN?