Equilibrium and nonequilibrium molecular dynamics methods for determining solid–liquid phase coexistence at equilibrium

Abstract

The solid–liquid equilibrium phase transition of a one-component Lennard-Jones system is determined by equilibrium and nonequilibrium molecular dynamics simulation methods. One method uses the observation that the scaling exponent of the pressure or energy of a shearing Lennard-Jones liquid is approximately 1 at the solid phase. This enables us to locate the density of the coexisting solid phase. The coexisting liquid phase density is then obtained by constructing a tie line between the coexisting solid phase point and the liquid phase curve. Alternatively, the coexisting liquid phase density can be efficiently obtained by observing the change in pressure as a function of strain rate and density. The coexisting solid phase density can be then obtained from a tie line from the liquid curve to the solid curve. These calculations are the first reported use of combined equilibrium and nonequilibrium molecular dynamics methods for phase coexistence at equilibrium. Our results are in very good agreement with those obtained by alternative simulation methods for phase equilibria.

Pressure dependence of confined liquid behavior subjected to boundary-driven shear

“…32 Perhaps relevant to this experimental study, Butler and Harrowell using boundary-driven shear NEMD, established the nature of two coexisting layers in relative sliding motion, in their case between a crystal and liquid phase. 33,34 Tribology is one area where the NEMD shear rate and film thickness can agree with experiment.…”

Recent developments and outstanding challenges in theory and modeling of liquid metals

“…The methods continue to be developed, and there is much recent literature on this topic [24,[26][27][28]83]. Several of the approaches utilize variations of the Gibbs-Duhem relationship [24,[26][27][28].…”

Application of kinetic Monte Carlo method to the vapour–liquid equilibria of associating fluids and their mixtures

“…The partial sum of the mobility, R k , is the sum of the mobilities from molecule 1 up to molecule k, inclusive. Equation (7) implies that a molecule is selected, according to its mobility, irrespective of which component in a mixture it belongs to.…”

“…Several recent simulations have explored different potential energy models in associating fluids. [1][2][3][4][5] There are a number of simulation methods that are available in the literature to predict the phase equilibrium [6][7][8], but the most generally favoured method for this purpose is the Monte Carlo (MC) simulation employing the Metropolis importance sampling algorithm [9,10] in the Gibbs ensemble Monte Carlo (GEMC) [2,3,[11][12][13][14][15][16] and this technique is recognised as the standard procedure. However, this method is unsatisfactory at low temperatures [17] because of the difficulty of inserting molecules into a dense phase.…”