Multilayer approximation for a confined fluid in a slit pore

G. J. Zarragoicoechea; A. G. Meyra; V. A. Kuz

doi:10.4279/pip.020002

Authors

G. J. Zarragoicoechea IFLYSIB, CICPBA, Universidad Nacional de La Plata, Argentina
A. G. Meyra IFLYSIB, CONICET, Universidad Nacional de La Plata, Argentina
V. A. Kuz IFLYSIB, CONICET, Universidad Nacional de La Plata, Argentina

DOI:

https://doi.org/10.4279/pip.020002

Keywords:

Confined fluid, Slit pore, van der Waals equation.

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.

Received: 23 December 2009, Accepted: 24 February 2010; Edited by: D. A. Stariolo; DOI: 10.4279/PIP.020002