Shear Viscosity of Model Mixtures by Nonequilibrium Molecular Dynamics III. Effect of Quadrupolar Interactions

Abstract

We present new results for thermodynamic properties and viscosities of pure quadrupolar fluids, a pure dipolar quadrupolar fluid, nonquadrupolar/quadrupolar mixtures, and quadrupolar/quadrupolar mixtures. It is evident that, the addition of quadrupolar interactions to the pure Ar and the addition of quadrupolar interactions to the pure dipolar Ar, leads to higher viscosities as was observed in the addition of dipolar interactions to the pure Ar [Lee and Cummings, J. Chem. Phys., 105, 2044 (1996)]. The total energies and the mixture densities show a linear dependence for both nonquadrupolar Ar/quadrupolar Kr (case B) and quadrupolar Ar/quadrupolar Kr (case C), and the linearity of case C is better than that of case B. This is not consistent with the idea that in the cases of the dipolar mixtures, dipolar/dipolar and nondipolar/nondipolar mixture are likely to be more ideal than nondipolar/dipolar mixtures. This is mainly due to the weaker interaction of quadrupole-quadrupole than that of dipoledipole.

Key Words:

• Shear viscosities
• Quadrupoles
• Nonequilibrium