I report calculations of the electronic structure of an ideal (undistorted) oxygen vacancy in rutile using the equation-of-motion method. I use a full phenomenological tight-binding Hamiltonian due to Vos to describe the electronic structure. The bulk band structure was also discussed in detail using the traditional Green's-function method. I illustrate an efficient way to calculate the perfect-crystal Green's-function matrix elements for any structure, including those that belong to non-symmorphic space groups. The results showed that the oxygen vacancy in rutile TiO2 results in deeply localized states in its vicinity.

Electronic Structure of a Single Oxygen Vacancy in Rutile TiO2. Tit, N.: Il Nuovo Cimento D, 1993, 15[11], 1405-14