Molecular modelling and simulation of the surface tension of real quadrupolar fluids. (6th January 2015) - Werth, Stephan
Abstract: Molecular modelling and simulation of the surface tension of fluids with force fields are discussed. Twenty-nine real fluids are studied, including nitrogen, oxygen, carbon dioxide, carbon monoxide, fluorine, chlorine, bromine, iodine, ethane, ethylene, acetylene, propyne, propylene, propadiene, carbon disulfide, sulfur hexafluoride, and many refrigerants. The fluids are represented by two-center Lennard–Jones plus point quadrupole models from the literature. These models were adjusted only to experimental data of the vapor pressure and saturated liquid density so that the results for the surface tension are predictions. The deviations between the predictions and experimental data for the surface tension are of the order of 20%. The surface tension is usually overestimated by the models. For further improvements, data on the surface tension can be included in the model development. A suitable strategy for this is multi-criteria optimization based on Pareto sets. This is demonstrated using the model for carbon dioxide as an example. Abstract : Graphical abstract: Abstract : Highlights: The vapor–liquid surface tension is computed for quadrupolar molecular models. On average, literature models overestimate the actual surface tension by about 20%. A multi-criteria optimization approach is applied to molecular models of CO2 .