Abstract: The lattice density functional theory (LDFT) for a Gibbs ensemble system of monoatomic molecules adsorbed in finite-width slits was modified by introducing the intermolecular-action-pair′s correction factor. The adsorption and desorption isotherms of solute were then calculated by a successive iteration procedure. The micro mechanisms of hysteresis loops are discussed by both the revised and original LDFT model. It is found that they can both predict hysteresis loops but large differences are found between results of them. As Monte Carlo simulation has demonstrated that revised model is more suitable to predict adsorbing properties in slits according to our former works, it can be concluded that the original LDFT model may arouse obvious system errors for its simple mean field assumption in theory treatments.

Key words: Hysteresis, LDFT, Slit adsorption, Gibbs ensemble