Prediction of experimental properties of CO$_2$ , improving actual force fields

Abstract

Most of the existing classical CO$_2$ models fail to reproduce some or many experimental properties such as surface tension, vapor pressure, density and dielectric constant at difference thermodynamic conditions. Therfore, it is proposed a new computational model to capture better structural, dynamical and thermodynamic properties for CO$_2$ . By scaling the Lennard Jones parameters and point charges; three target properties, static dielectric constant, surface tension and density, were used to fit actual experimental data. Moreover, by constructing a flexible model, effects of polarization might be included by variations of the dipole moment. Several tests were carried out in terms of the vapour-liquid equilibria, surface tensions and saturated pressures showing good agreement with experiments. Dynamical properties were also studied, such as diffusion coefficients and viscosities at different pressures, and good trends were obtained with experimental data.