A 3D non-local density functional theory for any pore geometry

• Published in: Molecular physics Vol. 118; no. 9-10; p. e1767308
• Main Authors: Bernet, Thomas, Piñeiro, Manuel M., Plantier, Frédéric, Miqueu, Christelle
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 01-06-2020; Taylor & Francis Ltd
• Subjects: Complex systems; Computation; Density functional theory; discrete geometry; Distribution functions; Fluid-solid interactions; fundamental-measure theory; Geometry; Physics; Porous materials; Radial distribution; Silicon dioxide; Zeolites
• ISSN: 0026-8976; 1362-3028
• DOI: 10.1080/00268976.2020.1767308

A general framework of classical non-local density functional theory (NLDFT) is presented, in order to consider the adsorption of spherical molecules in porous materials of any geometry. Fluid-fluid interactions and fluid-solid interactions can be repulsive or attractive. Some techniques that have been developed for the computation of weighted densities of hard-spheres are extended to attractive ones, in order to deal with an arbitrary pore geometry. This way, the computation method introduced in this work is validated by a comparison with analytical results for simple cases, and is directly applied to more complex systems. Density distributions depending on multi-dimensional effects are presented, and some radial distribution functions are recovered from NLDFT computations. Finally, the case of attractive continuous curved walls is detailed, which represents a large variety of real systems (e.g. micro and mesoporous silica, zeolites, carbonaceous nanoporous materials, etc.). With the new way of computation proposed, a general solution is presented, valid for any shape of continuous pore surface, by considering mathematical properties of discrete geometry due to the discretisation of the computational space with FFT computations.