Effect of pressure on OH and OD impurities in LiNbO3

The fundamental vibrational transition frequencies of OH and OD defects, as well as the first OH overtone and the vibrational-librational OH-combination band, are investigated in LiNbO3 under pressure using the diamond-anvil technique. The absorption bands shift to lower wavenumbers and become considerably broader at higher pressures. The experimental results are alternatively discussed within a single oscillator model and a recently developed model for hydrogen bonds in solids. (author)