Shear viscosity along the liquid-vapour coexistence

An analytical expression for the shear viscosity of a fluid with particles interacting via pairwise interaction of hard spheres plus an attractive Yukawa potential is presented. The impact of the kinetic pressure has been included following the thermodynamic energy equation and a non-empirical equation of state based on the inverse temperature expansion of the free energy from the mean spherical approximation. Viscosity is computed along the liquid-vapour coexistence curves for different ranges of attractive interactions. The viscosity's dependence on density and temperature up to the critical point has been investigated. The surface tension under similar conditions is also calculated and, therefore, the relation between surface tension and viscosity along the coexistence curve is established. The validity of the Arrhenius type empirical equation depicting the temperature dependence of viscosity in the vicinity and away from the critical point is also examined.