Distributed charge models of liquid methane and ethane for dielectric effects and solvation. (18th October 2021)

• Record Type: Journal Article
• Authors: Thakur, Atul C.; Remsing, Richard C.
• Is Part Of: Molecular physics. Volume 119:Number 19/20(2021)
• Publication Date: 2021-10-18
• Subjects: Liquid methane -- liquid ethane -- dielectric constant -- solvation -- Titan; Molecules -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Molécules -- Périodiques; Chimie physique et théorique -- Périodiques; 539.6.05
• DOI: 10.1080/00268976.2021.1933228
• Languages: English
• ISSNs: 0026-8976

Abstract

Abstract : Liquid hydrocarbons are often modelled with fixed, symmetric, atom-centred charge distributions and Lennard-Jones interaction potentials that reproduce many properties of the bulk liquid. While useful for a wide variety of applications, such models cannot capture dielectric effects important in solvation, self-assembly, and reactivity. The dielectric constants of hydrocarbons, such as methane and ethane, physically arise from electronic polarisation fluctuations induced by the fluctuating liquid environment. In this work, we present non-polarisable, fixed-charge models of methane and ethane that break the charge symmetry of the molecule to create fixed molecular dipoles, the fluctuations of which reproduce the experimental dielectric constant. These models can be considered a mean-field-like approximation that can be used to include dielectric effects in large-scale molecular simulations of polar and charged molecules in liquid methane and ethane. We further demonstrate that solvation of model ionic solutes and a water molecule in these fixed-dipole models improve upon dipole-free models. GRAPHICAL ABSTRACT: UF0001