Computing chemical potentials of adsorbed or confined fluids

TL;DR

This paper presents a new computational framework combining static structure factors, thermodynamic integration, and free energy perturbation to accurately compute the chemical potential of adsorbed or confined fluids, aiding in understanding their thermodynamics.

Contribution

The authors introduce a novel computational method that improves the calculation of chemical potentials for confined fluids from atomistic simulations.

Findings

Successfully applied to CO2 in MOFs

Accurately computed water in carbon nanotubes

Enhanced understanding of adsorption thermodynamics

Abstract

The chemical potential of adsorbed or confined fluids provides insight into their unique thermodynamic properties and determines adsorption isotherms. However, it is often difficult to compute this quantity from atomistic simulations using existing statistical mechanical methods. We introduce a computational framework that utilizes static structure factors, thermodynamic integration and free energy perturbation, for calculating the absolute chemical potential of fluids. For demonstration, we apply the method to compute the adsorption isotherms of carbon dioxide in a metal-organic framework (MOF) and water in carbon nanotubes.