Localization model description of diffusion and structural relaxation in superionic crystalline UO2

H Zhang and XY Wang and JF Douglas, JOURNAL OF CHEMICAL PHYSICS, 151, 071101 (2019).

DOI: 10.1063/1.5115067

We test the Localization Model (LM) prediction of a parameter-free relationship between the alpha-structural relaxation time tau(alpha) and the oxygen ion diffusion coefficient D-O with the Debye-Waller factor u(2) for crystalline UO2 under superionic conditions where large anharmonic interactions lead to non-Arrhenius relaxation and high ion mobility. As in a previous study of structural relaxation in Cu-Zr metallic glass materials having a range of compositions, we find that the LM relationship between the picosecond atomic dynamics (fast beta relaxation) and the long-time structural relaxation time and oxygen ion diffusion coefficient holds to an excellent approximation without any free parameters over the full range of temperatures and pressures investigated in our simulations.

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