Anomalous Specific Heat and Viscosity of Binary van der Waals Mixtures

This article investigates the behavior of several properties of a model binary van der Waals mixture near the solution critical point. The behavior of the heat capacity is determined from an exact analysis of the partition function. For the shear and bulk viscosity, the time dependence of the currents appearing in the time correlation function formulas is determined from linearized hydrodynamic equations. For the heat capacity and the shear viscosity the results of this model are identical to those originally obtained by Fixman by a different procedure. Comparison is also made with the results obtained by Zwanzig and Mountain for these quantities in a one-component van der Waals system near the liquid—vapor critical point. One finds, in qualitative agreement with available experiments, that the shear viscosity of a binary mixture diverges at the critical point.