Legendre-Fenchel transforms capture layering transitions in porous media
Abstract
We have investigated the state of a nanoconfined fluid in a slit pore in the canonical and isobaric ensembles. The systems were simulated with molecular dynamics simulations. The fluid has a transition to a close-packed structure when the height of the slit approaches the particle diameter. The Helmholtz energy is a non-convex function of the slit height if the number of particles does not exceed that of one monolayer. As a consequence, the Legendre transform cannot be applied to obtain the Gibbs energy. The Gibbs energy of a non-deformable slit pore can be transformed into the Helmholtz energy of a deformable slit pore using the Legendre-Fenchel transform. The Legendre-Fenchel transform corresponds to the Maxwell construction of equal areas.
Keywords
Cite
@article{arxiv.2111.15253,
title = {Legendre-Fenchel transforms capture layering transitions in porous media},
author = {Olav Galteland and Eivind Bering and Kim Kristiansen and Dick Bedeaux and Signe Kjelstrup},
journal= {arXiv preprint arXiv:2111.15253},
year = {2021}
}
Comments
12 pages, 10 figures