OH- absorption spectra of pure lithium niobate crystals

The OH- absorption spectra of congruent purr and nearly stoichiometric lith ium niobate crystals have been investigated. Experimental results show that each absorption band consists of three components. The OH- absorption peak s were considered to relate to the stretching vibration of protons located at 336 pm O-O bonds in oxygen triangles nearest to the Li site. The 3466 cm (-1) absorption peak corresponds to protons directly substituting for Li+ i ons; the 3481 and 3489 cm(-1) peaks are suggested to be associated with pro tons occupying intrinsic V-Li(-) defects near Nb-Li(5+) and two different i on environments cause these two absorption peaks.