Neutron irradiation and post-irradiation annealing under oxidising and reducing conditions were used to investigate H incorporation in, and the optical properties of, reduced (TiO2-x) rutile. Optical absorption in rutile was mainly due to a Ti3+ Ti4+ intervalence charge transfer effect. The main mechanism for H incorporation in rutile involves interstitial H not coupled to other defects, which had important implications for the rate of H diffusion, and possibly also on the electrical properties of rutile. Additional minor OH absorption bands in IR spectra indicate that a small amount of interstitial H was coupled to defects such as Ti3+ on the main octahedral site, and indicated that more than one H incorporation mechanism might operate. The concentration of oxygen vacancies had a controlling influence upon the H affinity of rutile

Neutron Irradiation and Post-Irradiation Annealing of Rutile (TiO2-x): Effect on Hydrogen Incorporation and Optical Absorption. Bromiley, G.D., Shiryaev, A.A.: Physics and Chemistry of Minerals, 2006, 33[6], 426-34