title: Thermodynamics of phase coexistence and metal-nonmetal transition in mercury: assessment of effective potentials via expanded Wang-Landau simulations.
abstract: We present molecular simulation results on the thermodynamics of phase transitions (specifically, the vapor-liquid and metal-nonmetal transitions) in mercury, as predicted by effective potential models. We use a recently developed method, known as Expanded Wang-Landau simulations, to determine the grand-canonical partition function of systems of mercury atoms. Using the statistical mechanics formalism, we are then able to determine all thermodynamic properties of the system, including the Gibbs free energy and entropy. Prior experimental and theoretical work has emphasized the strong interplay between the vapor-liquid coexistence and the metal-nonmetal transition. We therefore start by assessing the accuracy of the effective potentials considered in this work through a comparison to the available experimental data. We then analyze the thermodynamics of the nonmetal liquid-metal liquid transition, characterized by sharp variations in the rate of change of Gibbs free energy and enthalpy as a function of density. We also identify a crossover density (10.5 g/cm(3)) consistent with the results of recent ab initio calculations and with the experiment.
authors.affiliation: Department of Chemistry, University of North Dakota , Grand Forks, North Dakota 58202, United States.
authors.forename: Caroline
authors.initials: C
authors.lastname: Desgranges
authors.forename: Jerome
authors.initials: J
authors.lastname: Delhommelle