Vibrational spectroscopy of O-H and O-D centers in TiO$_{2}$

While the vibrational properties of O-H centers in TiO$_{2}$ have been studied for many years, recent experiments suggest a new picture of their behavior. In the 1970s, Bates and Perkins found a single, sharp, strongly polarized O-H line in TiO$_{2}$, and similarly for O-D and O-T [1]. On the contrary, recent studies by Herklotz \textit{et al.} [2] find three closely spaced O-H (O-D) lines that were assigned to two different charge states of an O-H (O-D) shallow donor. We have in our possession the very TiO$_{2}$ samples studied many years ago by Bates and Perkins. We have introduced H and D into these samples and also into TiO$_{2}$ samples obtained recently. High-resolution vibrational spectroscopy performed as a function of temperature at Lehigh provides new insight into the different vibrational properties seen for O-H in TiO$_{2}$ in the 1970's and in recent studies by Herklotz \textit{et al.} [1] J.B. Bates and R.A. Perkins, Phys. Rev. B \textbf{16}, 3713 (1977). [2] F. Herklotz \textit{et al.}, Phys. Rev. B \textbf{83}, 235202 (2011)..