The glass transition and diffusion in simulated liquid TiO₂

The glass transition and diffusion in liquid TiO₂ have been studied in a model containing 3000 atoms via molecular dynamics (MD) simulation. The density dependence of the glass transition temperature, T_g, of liquid TiO₂ has been found and is discussed. Diffusion of atomic species in 3.80 g cm^-3 TiO₂ models has been investigated over a wide temperature range from 2100 to 7000 K. We found that the temperature dependence of the diffusion constant of atomic species follows an Arrhenius law at relatively low temperatures above the melting point, and at higher temperatures it deviates from an Arrhenius law. Differences between the structures of amorphous TiO₂ models at three different densities in the range from 3.80 to 4.20 g cm^-3 have been found and are discussed. In addition, a transition from a low-density liquid (ldl) form to a high-density liquid (hdl) form was found and is discussed.