Oxygen vacancy diffusion in rutile was studied by Born-Oppenheimer molecular dynamics techniques in the framework of the semi-empirical molecular orbital method MSINDO. Migration of an O vacancy from the rutile (110) surface towards the bulk was simulated. The metadynamics technique was employed to accelerate the diffusion processes. In this way, transition state structures and activation energies for the diffusion processes were obtained. Rate constants and the time scale of diffusion processes were estimated for different temperatures using the calculated activation energy. It was found that the vacancies in the bulk were less stable than on the surface. The feasibility of O vacancy diffusion under experimental conditions was considered.

Molecular Dynamics Investigation of Oxygen Vacancy Diffusion in Rutile. Jug, K., Nair, N.N., Bredow, T.: Physical Chemistry and Chemical Physics, 2005, 7[13], 2616-21