Shear viscosity of liquid mixtures: Mass dependence

The expressions for zeroth, second, and fourth sum rules of the transverse stress autocorrelation function of a two-component fluid have been derived. These sum rules and Mori's memory function formalism have been used to study the shear viscosity of Ar-Kr and isotopic mixtures. It has been found that the theoretical result is in good agreement with the computer simulation result for the Ar-Kr mixture. The mass dependence of shear viscosity for different mole fractions shows that deviation from ideal linear model comes even from the mass difference in two species of the fluid mixture. At higher mass ratio, shear viscosity of the mixture is not explained by any of the empirical models.