Pressure Profile For An Associating Lennard-Jones Fluid Confined In A Spherical Cavity

We present the pressure tensor of an associating fluid confined in a spherical cavity of hard wall,where a high-order density correlation has been taken into account.Firstly,to give the two-body association potential for calculating the pressure tensor,an angle-average of site-site attraction over all orientations of two particles is performed.Secondly,the classical density functional theory is employed to obtain the density profile of the confined fluid under both open system and closed system,by which pressure profiles are illustrated under various conditions to show the dependence of the pressure tensor on the association strength,number of associating sites,radius of cavity,and bulk density(average particle number density).Thirdly,as an application,the corresponding surface tension and interfacial tension are calculated.Furthermore,the effect of the abovementioned factors on the surface tension and interfacial tension are discussed.Finally,we compare different influences between the open system and the closed system on pressure tensor,surface tension and interfacial tension.This paper aims to provide some help on physicochemical properties and aggregation structure of confined fluid.The content of the present paper is divided into four parts,which are listed as follows:Chapter I: Summary.This chapter gives the development of confined fluid and the classical density functional theory.Meanwhile,the general method of the classical density functional theory is outlined.And then the mechanics characteristics of confined fluid is introduced,such as pressure tensor,surface tension,interfacial tension.Chapter II: The pressure tensor of an associating LJ fluid of Af type confined in a spherical cavity(Grand Canonical Ensemble).According to the proposal due to Wertheim,an angle-average of site-site attraction over all orientations of two particles at a fixed distance is performed to give the two-body association.Furthermore,the classical density functional theory is employed to obtain the density profile of the confined fluid under open system,by which pressure profiles are calculated and illustrated under various conditions.Finally,as an application,the corresponding surface tension and interfacial tension under various conditions are calculated and analyzed.Chapter III: The pressure tensor of an associating LJ fluid of Af type confined in a closed spherical cavity(Canonical Ensemble).On the basis of the classical density functional theory,the density profile of the confined fluid under the closed system is obtained,by which pressure profiles are calculated and illustrated under various conditions.As an application,surface tension and interfacial tension under various conditions are calculated and analyzed.Then we compare different influences between the open system and the closed system on pressure tensor,surface tension and interfacial tension.Chapter IV: The shortcomings and prospects of this paper.