A mechanism of cation diffusion in ThO2 nanocrystal bulk. A molecular dynamic simulation.

A molecular dynamics simulation of the self-diffusion of thorium cations in ThO2 nanocrystals with a free surface is conducted. It is shown that a vacancy in the bulk of a crystal initiates a complex collective movement of cations, in which the interstitial positions surrounding the vacancy are involved. The diffusion coefficients of cations in the temperature range are calculated. The effective activation energy of diffusion is ED = (7.6 ± 0.7) eV. [ABSTRACT FROM AUTHOR]