Isotope effect in the diffusion of binary liquids

• Published in: Solid state communications Vol. 119; no. 2; pp. 73 - 77
• Main Author: Schober, H.R
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 06.07.2001; Elsevier
• Subjects: A. Disordered systems; Condensed matter: structure, mechanical and thermal properties; D. Phase transition; D. Thermodynamic properties; Diffusion and ionic conduction in liquids; Diffusion and thermal diffusion; Exact sciences and technology; Physics; Transport properties of condensed matter (nonelectronic); D. Phase transition; 66.10.−x; 64.70.Pf; 82.20.Tr; D. Thermodynamic properties; A. Disordered systems; Liquid state; Isotope effects; Temperature effects; Molecular dynamics calculations; Theoretical study; Diffusion; Lennard Jones model; Binary mixtures; Density; Self-diffusion
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/S0038-1098(01)00219-8

The diffusional isotope effect of a binary Lennard Jones liquid is calculated by molecular dynamics simulation. Mass differences of 20–40% were used. At equilibrium density, with decreasing temperature, a strong reduction of the isotope effect is found for both species. This indicates a marked increase of the collectivity of motion. On changing the density at a constant temperature the same effect is seen for the larger majority atoms, which shows that the density change is the main driving force behind the reduction of the isotope effect. Although the smaller minority atoms also show a drop in isotope effect with increasing density, the relation of the isotope effect to temperature and density differs between the two species.