Molecular dynamics simulations of diffusion in liquid GeO2 at 3000 to 5000K were performed. The densities ranged from 3.65 to 7.90g/cm3. The simulations were performed by using a model which contained 3000 particles and new interatomic potentials, for liquid and amorphous GeO2, which involved weak Coulomb interaction and Morse-type short-range interaction. A liquid–liquid phase transition, from a tetrahedral to an octahedral network structure, was found in simulated liquid GeO2 upon compression.

Such phase transition were accompanied by an anomalous diffusion of particles in liquid GeO2, such that the diffusion constant of both Ge and O particles increased strongly with increasing density (i.e. with increasing pressure) and went through a maximum at a density of about 4.95g/cm3. A possible relationship between the anomalous diffusion of particles and a structural phase transition in the system was considered.

Liquid–Liquid Phase Transition and Anomalous Diffusion in Simulated Liquid GeO2. V.V.Hoang, N.H.T.Anh, H.Zung: Physica B, 2007, 390[1-2], 17-22