Electronic structure of the ion pair model for Ti:Al₂O₃

Abstract

The Ti3+-Ti4+ ion pair is proposed experimentally to be responsible for the infrared residual absorption of Ti:Al2O3. However, no theoretical verification has been presented to date. In this paper, the DV-Xalpha calculation is performed upon clusters of (Ti3+O62-)9-, (Ti3+Al3+O92-)12- and (Ti3+Ti4+O92-)11-. Our work not only has interpreted the infrared residual absorption but also has clarified the confusion about the origin of the ultraviolet absorptions. Therefore the Ti3+-Ti4+ pair postulation is strongly supported by our present work.