Infrared spectra of hydrogen isotopes in potassium tantalate

The spectroscopic constants of hydroxyl ions formed from hydrogen, deuterium, and tritium in a potassium tantalate (KTaO3) host have been determined. These isotopes were found to diffuse readily either into or out of KTaO3 single crystals. At T=77 K the infrared absorption band due to the OH−, OD−, or OT− stretching vibration is extremely narrow (i.e., ∼1.0, 0.8, and 0.7 cm−1, respectively). These results indicate that the interaction between the hydroxyl ions and the surrounding lattice is very weak. The optical properties of hydroxyl ions and the characteristic features of hydrogen diffusion in KTaO3 are compared with those determined previously for aluminum oxide (Al2O3) and rutile (TiO2).