Fast estimation of ion-pairing for screening electrolytes: A cluster can approximate a bulk liquid

Abstract

The propensity for ion-pairing can often dictate the thermodynamic and kinetic properties of electrolyte solutions. Fast and accurate estimates of ion-pairing can thus be extremely valuable for supplementing design and screening efforts for novel electrolytes. Here, we introduce an efficient cluster model to estimate the local ion-pair potential-of-mean-force (PMF) between ionic solutes in electrolytes. The model incorporates an ion-pair and a few layers of explicit solvent in a gas-phase cluster and leverages an enhanced sampling approach to achieve high efficiency and accuracy. We employ harmonic restraints to prevent solvent escape from the cluster and restrict sampling of large inter ion distances. We develop a Cluster Ion-Pair Sampling (CLIPS) tool that implements our cluster model and demonstrate its potential utility for screening simple and poly-electrolyte systems.

References in corpus (6)

• PLUMED 2: New feathers for an old bird
• Well-Tempered Metadynamics: A Smoothly Converging and Tunable Free-Energy Method
• PLUMED: a portable plugin for free-energy calculations with molecular dynamics
• Rethinking Metadynamics: from bias potentials to probability distributions
• Quasi-Chemical Theory for Anion Hydration and Specific Ion Effects: Cl${}^{-}$(aq) \emph{vs.} F${}^{-}$(aq)
• Quasi-Chemical Theory with Cluster Sampling from Ab Initio Molecular Dynamics: Fluoride (F${}^{-}$) Anion Hydration