Study of some known regularities for the hard core one Yukawa and hard core double Yukawa fluids

Four known regularities; including the common bulk modulus, the common compression point, Tait-Murnaghan and the linear behavior of the P-T isochors; are investigated for the hard core one Yukawa (HCOY) and hard core double Yukawa (HCDY) fluids. It is shown that the HCOY fluid is not able to predict the common bulk modulus and the common compression points properly. While, these regularities are observable in the HCDY fluids and it can be shown that the common intersection point occurs where contribution of the repulsion terms to the equation of state is equal to that of attraction terms. The effect of hard core potential shape on these regularities is also investigated. The results show that the application of the hard convex core in HCDY equation of state just affect the common bulk modulus and common compression points slightly, but has no significant effect on other studied regularities.

It is shown that in the common intersection point, average intermolecular distance is such that the attraction and the repulsion effects cancel each others.Highlights► Four dense fluid regularities are investigated for Yukawa fluids. ► The attraction and the repulsion roles of potential in these regularities are investigated. ► The hard core double Yukawa potential can show some dense system regularities. ► The common intersection point is occurred in a specific density. ► In the intersection point density, the attraction and the repulsion contributions cancel each other.