Aim to accurately predict the thermodynamic properties of n-alkanes and their mixtures at different temperature

in this paper

the non-bond Lennard-Jones (L-J) interaction parameter

ε

was optimized by using n-C4-C10 as the training set and all-atom molecular dynamics simulations. Here an empirical relationship between the L-J parameter (ε) and the reduced temperature (Tr) and carbon atomic number of n-alkanes (NC) was obtained. According to above-mentioned relationship

the values of ε at different temperatures were successfully calculated. Further

the properties of viscosity

density and diffusion coefficient of different n-alkanes and their mixtures were predicted using traditional and non-equilibrium molecular dynamics simulations with all-atom OPLS-AA force field corrected by temperature-dependent ε. Compared with previous theoretical prediction values and experimental data

the prediction with temperature-dependent ε showed that the physical properties of n-alkanes and their mixtures predicted by this method were in the best agreement with the experimental values. The relative deviations between the predicted values of density

viscosity and diffusion coefficient and their corresponding experimental counterparts were less than 2%

5% and 10%

respectively. The new predicted values are significantly superior to those predicted by both other theoretical methods and molecular dynamics simulations with the original OPLS-AA force field. Therefore

the established temperature-dependent force field has important practical application value for accurately predicting the thermodynamic properties of n-alkanes and their mixtures by molecular dynamics simulations.