The fundamental vibrational transition frequencies of OH and OD defects, as well as the first OH overtone and the vibrational-librational OH-combination band, were investigated under pressure by using the diamond-anvil technique. The absorption bands shifted to lower wave-numbers and became considerably broader at higher pressures. The results were explained in terms of a single oscillator model, and a new model for H bonds in solids.

Effect of Pressure on OH and OD Impurities in LiNbO3. P.G.Johannsen, V.Schäferjohann, S.Kapphan: Journal of Physics - Condensed Matter, 1999, 11[2], 583-91