Towards Open Boundary Molecular Dynamics Simulation of Ionic Liquids

TL;DR

This paper extends the adaptive resolution molecular dynamics method to ionic liquids, enabling open boundary simulations by effectively modeling charged particles and system-reservoir interactions.

Contribution

It introduces two approaches for coarse-grained modeling of charged ionic liquids within the GC-AdResS framework, demonstrating their effectiveness.

Findings

Successful simulation of ionic liquids with open boundaries.

Validation of coarse-grained reservoir models for charged particles.

Paves the way for multiscale ionic liquid analysis.

Abstract

We extend the use of the adaptive resolution method (AdResS) in its Grand Canonical-like version (GC-AdResS) to the molecular dynamics simulation of 1,3-dimethylimidazolium chloride. We show that the partitioning of the total system in a subsystem of interest with atomistic details and a reservoir of coarse-grained particles leads to satisfactory results. The challenging aspect of this study, compared to previous AdResS simulations, is the presence of charged particles and the necessity of addressing the question about the minimal physical input needed to model the coarse-grained particles in the reservoir. We propose two different approaches and show that in both cases they are sufficient to capture the decisive physical characteristics that allow a valid system-reservoir coupling. The technical satisfactory result paves the way for multiscale analysis of ionic liquids and for truly open boundary molecular simulations.