Surface term for the capillary condensation transitions in a slit geometry

TL;DR

This paper improves a simple fluid model for capillary condensation in slit geometries by modifying the surface term, leading to better agreement with density-functional calculations for helium at zero temperature.

Contribution

It introduces a corrected surface term in the simple fluid model that enhances its accuracy in predicting phase transitions in capillary systems.

Findings

Enhanced model aligns closely with density-functional results

Correction depends on adsorption potential strength

Improved predictions for helium phase transitions

Abstract

It is shown that a bare simple fluid model (SFM) proposed some years ago for studying adsorption between two semi-infinite solid walls can be improved by modifying the surface term in the grand potential for the film phase. Such a correction substantially improves the agreement between the predictions for phase transitions provided by that SFM and results obtained from calculations carried out for $^4$He with the density-functional method at zero temperature. The corrective term depends on the strength of the adsorption potential and observables of bulk helium.