Simulation studies on mixtures of dipolar with nonpolar linear molecules II. A mixing rule for the dipolar contribution to the Helmholtz energy

In recent equations of state an explicit expression for the dipolar contribution to the Helmholtz energy FD is used. If such equations are applied to mixtures the problem of mixing rules for FD arises. As a solution, a “one-fluid dipole moment μx” is introduced which is based on perturbation theory. The accuracy of the approach is tested by simulation results for mixtures of dipolar with nonpolar linear molecules. In addition to the simulation runs from Part I (Müller et al. (1994)), results from 97 new NVT simulations are presented. Comparisons of pressures, internal energies, dipole energies and excess free energies from simulations with those obtained from the equation for FD in combination with the one-fluid dipole moment μx shows good to excellent agreement.