Local structure and oxide-ion conduction mechanism in apatite-type lanthanum silicates.

The local structure of apatite-type lanthanum silicates of general formula La(SiO)O has been investigated by combining the atomic pair distribution function (PDF) method, conventional X-ray and neutron powder diffraction (NPD) data and density functional theory (DFT) calculations. DFT was used to build structure models with stable positions of excess oxide ions within the conduction channel. Two stable interstitial positions were obtained in accordance with literature, the first one located at the very periphery of the conduction channel, neighbouring the SiO tetrahedral units, and the second one closer to the channel axis.

Atomistic simulations of TeO₂-based glasses: interatomic potentials and molecular dynamics.

In this work we present for the first time empirical interatomic potentials that are able to reproduce TeO2-based systems. Using these potentials in classical molecular dynamics simulations, we obtained first results for the pure TeO2 glass structure model. The calculated pair distribution function is in good agreement with the experimental one, which indicates a realistic glass structure model.