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Influence of mass difference on dynamic properties of isotope mixtures

N. Kiriushcheva·S. V. Kuzmin
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Abstract

We present the results of a Molecular Dynamics computer simulations of a two component isotope mixture of Lennard-Jones particles, monodisperse in size but different in masses, at a fixed average density and temperature. We study changes in properties that result from mass heterogeneity, by measuring the pair distribution function, diffusion coefficient, velocity autocorrelation function, non-Gaussian and isotope effect parameters, as functions of the degree of mass difference. Our results show that if static properties are not influenced by a variation of mass variation, the dynamic properties are significantly affected and even exhibit the presence of ``critical'' values in the mass difference. We also demonstrate that our model gives a simple contra example to a recently proposed a universal scaling law for atomic diffusion in condensed matter [M. Dzugudov, Nature, v.381, 137 (1996)].

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N. Kiriushcheva, S. V. Kuzmin. 2003-11-12. Influence of mass difference on dynamic properties of isotope mixtures. https://arxiv.org/abs/cond-mat/0311290

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