Fast event-driven simulations for soft spheres: from dynamics to Laves phase nucleation

TL;DR

This paper demonstrates that event-driven Monte Carlo simulations can efficiently and accurately reproduce the static and dynamic properties of soft sphere systems, enabling exploration of phase behavior and nucleation at very low temperatures.

Contribution

It introduces and validates an event-driven Monte Carlo method as a faster alternative to molecular dynamics for simulating steeply interacting particles.

Findings

EDMC reproduces static thermodynamic properties accurately.

EDMC is over ten times faster than MD at low temperatures.

Laves phase nucleation occurs at lower temperatures than previously known.

Abstract

Conventional molecular dynamics (MD) simulations struggle when simulating particles with steeply varying interaction potentials, due to the need to use a very short time step. Here, we demonstrate that an event-driven Monte Carlo (EDMC) approach first introduced by Peters and de With [Phys. Rev. E 85, 026703 (2012)] represents an excellent substitute for MD in the canonical ensemble. In addition to correctly reproducing the static thermodynamic properties of the system, the EDMC method closely mimics the dynamics of systems of particles interacting via the steeply repulsive Weeks-Chandler-Andersen (WCA) potential. In comparison to time-driven MD simulations, EDMC runs faster by over an order of magnitude at sufficiently low temperatures. Moreover, the lack of a finite time step in EDMC circumvents the need to trade accuracy against simulation speed associated with the choice of time step in MD. We showcase the usefulness of this model to explore the phase behavior of the WCA model at extremely low temperatures, and to demonstrate that spontaneous nucleation and growth of the Laves phases is possible at temperatures significantly lower than previously reported.