Investigation about suitability of hard core attractive Yukawa potential as a model potential for short-range attractive interactions in colloidal dispersions

Abstract

An investigation is carried out about the suitability of mapping attractive short-range potential of colloidal systems onto both hard core attractive Yukawa (HCAY) potential and adhesive hard sphere (AH) potential for prediction of the solid–liquid (S–L) transition. Asakura and Oosawa's depletion potential of asymmetrical binary hard sphere mixture is taken as example of the attractive short-range potential. The S–L transition of the AH potential is based on a modified weighted density approximation, and that of the HCAY potential is based on first order thermodynamic perturbation theory for solid phase and a recently proposed analytical expression for the free energy of fluid phase. It is found that the second virial coefficient can be served as a tool for mapping between similar but different potentials for the case of S–L transition as well as for the case of fluid structure properties, and the HCAY potential is more suitable as a mapping potential than the AH potential.