J Chem Phys. 2010 Dec 14;133(22):224301. doi: 10.1063/1.3517867.

Equation of state and liquid-vapor equilibrium of polarizable Stockmayer fluids.

The Journal of chemical physics

Adrián Rocha-Ichante, Fernando del Río, Edgar Ávalos

PMID: 21171683 DOI: 10.1063/1.3517867

Abstract

In this work we develop the concept of an effective potential to obtain the equation of state of polarizable Stockmayer (PSM) fluids. This potential consists of a Lennard-Jones function with appropriate energy and distance parameters that depend on the reduced dipolar moment μ(∗) and polarizability α(∗). The approach deals accurately with polarizable SM fluids with μ(∗)≤2.0 and α(∗)≤0.1. However, prediction of second virial coefficients is reliable up to μ(∗)≤4.0. When the low-density sphericalized potential is used at moderate and large densities, the effect of the dipole-dipole attraction is overestimated in agreement with an effect previously found in the literature. This effect can be traced back to a frustration mechanism due to the interaction between three and more dipoles. We propose a model to account for this frustration effect and are able to reproduce the vapor-liquid equilibrium of polarizable SM fluids in agreement with simulated results from the literature. Molecular dynamics simulations were carried out to show that the effective SM fluid has a radial distribution function very close to that of the true SM system.

Publication Types

• Journal Article