Nonequilibrium Molecular Dynamics of a Dense Ionic Fluid

Abstract

Although the structural and transport properties of molten salts have been frequently examined in equilibrium molecular dynamics (MD) simulations, relatively little is known about these systems in nonequilibrium conditions. In this article we report results from nonequilibrium molecular dynamics (NEMD) simulations of a dense ionic fluid composed of charged soft spheres and compare these with equilibrium MD simulation data for the same system. Using Gaussian isokinetic equations of motion, the response of the system to applied electrical fields, varying in magnitude and frequency, was investigated in detail. The frequency dependent electrical conductivity was evaluated in nonequilibrium conditions and was found to be in good quantitative agreement with the spectrum of current fluctuations in the equilibrium ensemble. In order to follow the distortion of the liquid structure in external electric fields we also considered the direction-dependent distributions of charges in an ionic flow.

Key Words:

• Dense ionic fluid
• nonequilibrium dynamics