Investigation of the mass dependence of self-diffusion coefficients by molecular dynamics calculations: binary and ternary isotopic mixtures of atoms
1999; Taylor & Francis; Volume: 96; Issue: 8 Linguagem: Inglês
10.1080/00268979909483061
ISSN1362-3028
Autores Tópico(s)Material Dynamics and Properties
ResumoExtensive molecular dynamics calculations have been used to study for the first time systematically the dependence of the self-diffusion coefficients Di (i = 1, 2, 3) in binary and ternary atomic isotopic mixtures on the particle mass ratios m*2 = m 2/m 1 and m*3 = m 3/m 1 at different reduced temperatures T* and reduced particle number densities n*, using a Lennard-Jones 12-6 potential and a hard-soft-spheres potential. In addition, the dependence of Di values of binary mixtures on the mole fraction x 1 = 1—x 2 was also investigated for some thermodynamic states. The calculated values of Di can be represented quantitatively by exponential estimates of the form Di = D* i (m*2)ex i in the case of binary mixtures and Di = D 0 i (m*2)ex i (m 3)ext i in the case of ternary mixtures. D 0 i are the self-diffusion coefficients in reference mixtures of mass ratios m*2 = m*3 = 1. The dependence of the exponents ex i (m*2, T*, n*, x 1) of binary mixtures on m*2, T*, n*, and x 1 and the dependence of the exponents ext i (m*2, m*3, n*) of equimolar ternary mixtures at T* = 1.8 on the exponents ex i of the constituent binary mixtures and on m*2, m*3, and n* are discussed.
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