The presence of Cu+ in OH-doped crystals led to several new infra-red absorption bands with a half-width of about 0.2/cm at 100K. Their relative intensities were strongly dependent upon the impurity concentration. They were attributed to various vibrational internal modes of molecular OH- that was perturbed by neighboring Cu+ ions. The temperature dependence of several OH- side-bands around the so-called free OH- stretching mode at 3737.8/cm was reported. The temperature dependence revealed a behavior that was different to that observed for OH- quasi-free rotors in some Cs halides. At temperatures ranging from 100 to 300K, the free OH- half-width exhibited a T2 behavior. For 3 chosen absorption side-bands, the dependences were of the form: T1.6, T1.8 or T2.5. The lack of any observable thermally stimulated depolarization current or electric field-induced dichroism indicated that the OH- was frozen-in, as in the case of OH--Cu+ pairs.

J.L.Fabris, M.Müller, A.C.Hernandes, M.Siu-Li, S.Kapphan: Radiation Effects and Defects in Solids, 1995, 134, 353-6