Density profiles of a double square-well model of a chemically associating fluid near a hard wall

Abstract

Density profiles of a double square-well model of a chemically associating fluid near a hard wall are studied using integral equations and computer simulation techniques. The model of the bulk fluid is a two-component system of ‘hard’ spheres which, if of different species, are able to overlap and form dimers. This kind of transformation represents a chemical reaction between monomeric units and is generated by an interparticle interaction in the form of an intracore attractive double square well. The dimers which consist of the same species, but differ in the bonding length, are treated as isomers of the product of the reaction of dimerization. Peculiarities in the behaviour of the bulk fluid influence the density profiles and the absorption of particles at a hard wall. The effects of chemical reaction, the bulk density, and energetic characteristics of each of the attractive wells on the density profiles are investigated. The theory is compared with Monte Carlo computer simulation data.