Multilayer approximation for a confined fluid in a slit pore

TL;DR

This paper introduces a multilayer model for a confined Lennard-Jones fluid in a slit pore, deriving analytical expressions and validating results against simulations and experiments.

Contribution

The study develops an analytical multilayer approximation for confined fluids, enabling explicit calculations of density profiles and pressures in slit nanopores.

Findings

Excellent agreement with Monte Carlo simulations

Accurate predictions of nitrogen density profiles

Validated against experimental data

Abstract

A simple Lennard-Jones fluid confined in a slit nanopore with hard walls is studied on the basis of a multilayer structured model. Each layer is homogeneous and parallel to the walls of the pore. The Helmholtz energy of this system is constructed following van der Waals-like approximations, with the advantage that the model geometry permits to obtain analytical expressions for the integrals involved. Being the multilayer system in thermodynamic equilibrium, a system of non-linear equations is obtained for the densities and widths of the layers. A numerical solution of the equations gives the density profile and the longitudinal pressures. The results are compared with Monte Carlo simulations and with experimental data for Nitrogen, showing very good agreement.