Effect of sharp maximum in ion diffusivity for liquid xenon

31st International Conference on Equations of State for Matter

Lankin, A.V.^1 ; Orekhov, M.A.^1,2

Joint Institute for High Temperatures of the Russian Academy of Sciences, Izhorskaya 13, Moscow

125412, Russia^1

Moscow Institute of Physics and Technology, Institutskiy Pereulok 9, Dolgoprudny, Moscow Region

141700, Russia^2

关键词: Classical molecular dynamics;    Ion diffusion;    Ion diffusion coefficient;    Ion movements;    Jump diffusion;    Qualitative model;    Small region;    Stable region;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/774/1/012035/pdf
DOI  :  10.1088/1742-6596/774/1/012035

来源: IOP

【 摘 要 】

Ion diffusion in a liquid usually could be treated as a movement of an ion cluster in a viscous media. For small ions this leads to a special feature: diffusion coefficient is either independent of the ion size or increases with it. We find a different behavior for small ions in liquid xenon. Calculation of the dependence of an ion diffusion coefficient in liquid xenon on the ion size is carried out. Classical molecular dynamics method is applied. Calculated dependence of the ion diffusion coefficient on its radius has sharp maximums at the ion radiuses 1.75 and 2 Å. Every maximum is placed between two regions with different stable ion cluster configurations. This leads to the instability of these configurations in a small region between them. Consequently ion with radius near 1.75 or 2 Å could jump from one configuration to another. This increases the speed of the diffusion. A simple qualitative model for this effect is suggested. The decomposition of the ion movement into continuous and jump diffusion shows that continuous part of the diffusion is the same as for the ion cluster in the stable region.