The O isotope shifts of the vibrational modes of interstitial O, in isotopically enriched samples, were compared with the predictions of calculations that were based upon a bond-centered location for the O atom, as deduced from first principles. This comparison confirmed the existence of a Raman-active mode in which the O atom was weakly involved, and of a resonance which produced a broadening and small shift of the 17O asymmetrical mode.

B.Pajot, E.Artacho, C.A.J.Ammerlaan, J.M.Spaeth: Journal of Physics - Condensed Matter, 1995, 7[35], 7077-85