Investigation of the mass dependence of self-diffusion coefficients by molecular dynamics calculations: binary non-isotopic mixtures of atoms

Extensive molecular dynamics calculations have been used to study systemati cally for the first time the dependence of the self-diffusion coefficients D-i (i = 1, 2) in binary equimolar nonisotopic atomic mixtures (mole fracti ons x(1) = x(2) = 0.5, reduced temperature T* = 1.6) on the particle mass r atio m(2)* = m(2)/m(1) (1 less than or equal to m(2)* less than or equal to 16.5) in the ranges of reduced particle number density 0.15 less than or e qual to n* less than or equal to 0.85 and reduced length parameter 0.5 less than or equal to sigma(22)* less than or equal to 2.0 for a Lennard-Jones 12-6 potential. The calculated D-i values can be represented quantitatively by an exponential estimate of the form: D-i = D-i(0)(m(2)*)(exi). D-i(0) a re the self-diffusion coefficients in reference mixtures with m(2)* = 1. Th e observed dependence of the exponents ex(i)(m(2)*, n*, sigma(22)*) on m(2) *, n* and sigma(22)* is discussed in this paper.