A New Equation of State for the Square Well Fluids

The square-well potential function is considered as the superposition of hard sphere potential and a short range uniform negative potential. From this,the corresponding equation of state which contains two localized radial distribution functions is derived by statistical mechanics. The molecular dynamic data of compressibility factor are used to regress this two localized radial distribution functions. Therefore, a new equation of state of square well fluids is established. Its attractive term is much simpler than that proposed by Alder et al. and the consistency with MD data for compressibility factor is also better at the area of higher densities.