Temperature dependence of coarse-grained potentials for liquid hexane

Abstract

The present molecular dynamics study is an investigation of the temperature (T) dependence of liquid hexane coarse-grained potentials optimized with the Iterative Boltzmann Inversion method. An approach for the derivation of coarse-grained potentials at temperatures T different from the optimization temperature T₀ has recently been proposed for ethylbenzene. This method is based on the use of a T-dependent scaling factor f(T) to generate ethylbenzene potentials at T ≠ T₀. The approach is here extended to hexane, considering different reference temperatures T₀ and functional forms for f(T). From our simulations, it appears that the accuracy of the temperature transferability depends simultaneously on the T₀ chosen and the analytic form of f(T). Such a behavior is suppressed by the use of a new 2-point interpolation formula to generate coarse-grained potentials as a function of T. This scheme employs a linear interpolation based on the optimization of coarse-grained potentials at two reference temperatures, T_L and T_U, with T_L ≤ T ≤ T_U. Accurate coarse-grained simulations of liquid hexane can be performed using the new interpolation scheme. The results are encouraging for the use of potential interpolations as a practical means for devising coarse-grained potentials within a wider temperature range.