An effective pair potential for thermodynamics and structural properties of liquid mercury

Abstract

The properties of liquid mercury are investigated by using an empirical effective pair potential. Its parameters are determined with the aid of Monte Carlo simulation along the liquid branch of the liquid-vapor coexistence curve. The complexity of the electronic structure of dense metal mercury supposes a state dependence of the interatomic interactions, while no more state dependence is found in the metal-nonmetal transition region. It is shown that the use of this effective potential leads to an accurate description of the structural and thermodynamic properties of the expanded liquid mercury. Then, the melting and freezing phenomena are investigated with that potential. Sharp melting and freezing temperatures are observed at 234 and 169 K, respectively. This large hysteresis loop between freezing and melting is consistent with the experiments for the bulk mercury.

Surface tension of liquid mercury: a comparison of density-dependent and density-independent force fields

“…high surface tension and dense liquid) at experimentally important tem-peratures is the necessary starting point for the large-scale MD simulation of SAM-Hg or other interfacial systems and phase coexistences involving liquid mercury. The need to reproduce unique properties of liquid Hg has generated over the last decades a number of works [53][54][55][56][57][58][59][60][61][62][63][64][65]73] all underlining the importance of the state-dependent interactions, either through temperature or density, to mimic intricate many-body effects due to the complicated underlying electron structure of liquid Hg. As was previously discussed by Louis, an empirical inclusion of a density dependence in a pair potential requires additional care when used [66].…”

Structure of free surface crystallization of Hg: a first attempt

“…Additional details are given in Ref. [8]. In the present study, forces acting on the atoms have been computed with…”

“…To date, the x-ray reflectivity data for l-Hg at both melting and room temperatures [11], have only been reproduced recently by theoretical calculation including self-consistent classical simulations [9]. For the present investigation, we have used an interaction model, developed in a previous work [8] that reads…”

“…In addition, the emphasis on the existence of the T/T C threshold has been straightforward supported by very recent X-ray reflectivity experiments, on the one hand, showing surface layering in molecular non-liquid-crystalline, nonmetallic liquids with low T M /T C ratios [6], and by computer simulation studies on the other hand, predicting a significant structure, extending several atomic layers into the bulk liquid-Hg (l-Hg) at room and melting temperatures [7]. In the latter study, an accurate broad and shallow pair interaction model, presenting no Friedel oscillations has been used [8].…”

“…This has been carried out by using molecular dynamics method, where the forces acting on the atoms are computed from a simple pair interaction model [8], resulting from a low freezing point (T M ~ 235K) and a high critical point (T C ~ 1750K). By investigating the behaviour of both DP and in-planestructure in conditions that are not yet accessible to experimental measurements, some state transitions are met.…”