Pair entropy and universal viscosity scaling for molecular systems via molecular dynamics simulations

Journal of Molecular Liquids. 2022. Vol. 368. Article 120714.

Nikitiuk B., D. I. Salikova, N. D. Kondratyuk, V. V. Pisarev

The scaling between the excess entropy and transport coefficients of liquids is an interesting property found by Rosenfeld in atomistic simulations. Later, Dzugutov proposed to estimate the excess entropy on the basis of the pair entropy. That approach has been shown to work well for atomic liquids and rigid molecules, but there is a problem of pair entropy definition for molecular substances in general.
In this work, we propose a new method of estimation of the pair contribution to the excess entropy for hydrocarbon
liquids. We present the results on viscosity-excess entropy and viscosity-pair entropy Rosenfeld scaling for linear alkanes and an aromatic compound in two different force fields, and compare the results with the available experimental and correlation data. We show that our method accounts for 75-90% of excess entropy changes in molecular liquid, comparable to the pair entropy contribution in atomic liquids. 

Keywords: calculation of entropy, молекулярное моделирование, molecular modeling, вязкость, hydrocarbons, углеводороды, shear viscosity, конфигурационная энтропия, configurational entropy

Publication based on the results of: New technologies of supercomputer modeling in material science (2023)