Comparison of Force Fields for the Prediction of Thermophysical Properties of Long Linear and Branched Alkanes

The prediction of thermophysical properties at extreme
conditions
is an important application of molecular simulations. The quality
of these predictions primarily depends on the quality of the employed
force field. In this work, a systematic comparison of classical transferable
force fields for the prediction of different thermophysical properties
of alkanes at extreme conditions, as they are encountered in tribological
applications, was carried out using molecular dynamics simulations.
Nine transferable force fields from three different classes were considered
(all-atom, united-atom, and coarse-grained force fields). Three linear
alkanes (n-decane, n-icosane, and n-triacontane) and two branched alkanes (1-decene trimer
and squalane) were studied. Simulations were carried out in a pressure
range between 0.1 and 400 MPa at 373.15 K. For each state point, density,
viscosity, and self-diffusion coefficient were sampled, and the results
were compared to experimental data. The Potoff force field yielded
the best results.