Single-simulation determination of phase boundaries: A dynamic Clausius–Clapeyron integration method

Abstract

We present a dynamic implementation of the Clausius–Clapeyron integration (CCI) method for mapping out phase-coexistence boundaries through a single atomistic simulation run. In contrast to previous implementations, where the reversible path of coexistence conditions is generated from a series of independent equilibrium simulations, dynamic Clausius–Clapeyron integration (d-CCI) explores an entire coexistence boundary in a single nonequilibrium simulation. The method gives accurately the melting curve for a system of particles interacting through the Lennard-Jones potential. Furthermore, we apply d-CCI to compute the melting curve of an ab initio pair potential for argon and verify earlier studies on the effects of many-body interactions and quantum effects in the melting of argon. The d-CCI method shows to be effective in both applications, giving converged coexistence curves spanning a wide range of thermodynamic states from relatively short nonequilibrium simulations.

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].…”

“…Several of the approaches utilize variations of the Gibbs-Duhem relationship [24,[26][27][28]. A more direct approach is to use perturbation from hard-sphere systems, utilizing the Weeks-Chandler-Anderson (WCA) [84,85] approach.…”

“…Phase diagrams, including melting curves [21][22][23][24][25][26][27][28], solidus and liquidus lines [29][30][31][32][33][34][35], are difficult to predict accurately without experimental input, even for simple binary systems [30][31][32][33]. Some of this review will specifically focus on equilibrium properties of solid-liquid interfaces [3,9,12,[16][17][18][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54], including their free energies and mobilities.…”

Molecular dynamics studies of melting and liquid properties of ammonium dinitramide

“…1,2 Experimentally, it has been observed that the melting of crystalline materials is facilitated by introducing heterogeneous nucleation sites at the surface of the solid. [3][4][5] By suppressing surface nucleation, melting must occur by homogeneous nucleation in the bulk solid and it becomes possible to superheat the crystal.…”

Reversible scaling simulations of the melting transition in silicon

“…7,8 These authors have shown that the AS technique can also be used to evaluate the free energy not at a single temperature, but in a predefined temperature range. They first showed that, in terms of the free energy, there is an exact equivalence between changing the temperature while keeping the potential energy function fixed, and fixing the temperature while scaling the potential.…”