Open AccessA locally analytic density functional theory describing adsorption and condensation in microporous materials
Author(s) -
Robert H. Nilson,
Stewart K. Griffiths
Publication year - 1997
Language(s) - English
Resource type - Reports
DOI - 10.2172/477615
Subject(s) - gravitational singularity , density functional theory , microporous material , van der waals force , condensation , range (aeronautics) , statistical physics , distribution (mathematics) , integral equation , physics , thermodynamics , classical mechanics , computational chemistry , materials science , mathematics , chemistry , mathematical analysis , quantum mechanics , molecule , composite material
The fluid density distribution within microscopic pores is determined by solving integral equations relating to the local chemical potential to the Van der Waals attractions and hard sphere repulsions of surrounding material. To avoid resolving the density distribution on sub-molecular scales, the governing equations are averaged over zones of molecular size using analytic functions to represent local density variations within each zone. These local density profiles range form singularities to uniform distributions depending on the local variation of the potential field. Sample calculations indicate that this integral approach yields results in very good agreement with those based on traditional density functional theory (DFT), while reducing computing times by factors of 10{sup 3} to 10{sup 4} for one- dimensional geometries