A 2-D molecular dynamics simulation of the effects of coulombic versus multipolar intermolecular potential for a fluid

Abstract

The aim of this paper is to compare the effects of the discrete charge versus the multipolar model on the static and dynamical properties of a fluid whose molecules possess a permanent distribution of charges. For this goal simulation by ‘molecular dynamics’ is employed. A two-dimensional system is adopted in order to minimize possible errors due to the periodic boundary conditions. A steric (Lennard-Jones triatomic) potential is added to the electric ones. The present computations relate to the dipole versus two-discrete-charges comparison; the density lies in the intermediate range and two temperatures are studied. One observes substantial differences at low temperature between the two models. These differences disappear when the temperature is increased. Important differences between the combined steric and electric and the steric potential alone are also observed.