Computation of transport coefficients of liquid benzene and cyclohexane using rigid multicenter pair interaction models

Abstract

With the use of multicenter Lennard-Jones pair potentials, the liquids benzene and cyclohexane were studied by molecular-dynamics computations. The experimental atomic structure of the molecules was essentially kept by the rigid molecule models. However, the H atoms were only indirectly taken into account. Shear viscosity and thermal conductivity coefficients and the corresponding time correlation functions were determined and their dependence on system size and averaging level investigated. It was found that the time correlation functions must be integrated over extremely long times compared with atomic Lennard-Jones liquids to obtain reliable plateau values for the shear viscosity. The transport coefficients finally resulting from our expansive molecular-dynamics runs agree well with the measured data for the chosen eight liquid states. Apparently, the rigid polycenter interaction models work well for the description of the complicated potential interaction in molecular liquids both for static and dynamic properties.