On the use of transport properties to discriminate Mie-type molecular models for 1-propanol optimized against VLE data

Abstract

Parameterization of classical force fields often suffers from highly correlated parameters. In the present work the hypothesis that transport properties such as shear viscosity or self-diffusion coefficient can be used to decouple force field parameters that were fitted to static thermodynamic properties, such as saturation vapor pressure and liquid density is investigated. Here 1-propanol was studied where united-atom sites are described through Mie potentials and point charges. Four models were selected that gave about the same level of agreement with experimental liquid densities and vapor pressures. Shear viscosity and self-diffusion coefficients were evaluated with the aim to discriminate the models. However, the degeneracy of force field parameters observed in the static properties was also observed in the dynamic properties. We conclude that meaningful parameterizations for transferable force fields should simultaneously consider several molecules from a homologous series in order to define a less degenerate optimization problem.