Determination of ISM equation of state for liquids from surface energy: a simplified procedure for mixtures

To determine the ISM equation of state, we have established a new reduced temperature scale TEs∗=TEs∗(T;Es,ρf), where T is the absolute temperature, Es and ρf are surface energy and the liquid density at the freezing temperature, respectively. The reduced second virial coefficient B2∗ follows a promising corresponding states correlation for a number of spherical, linear and long chain hydrocarbons liquids, allowing prediction of B2(T) in the desire temperature range. Then it follows that all three temperature-dependent parameters of the ISM equation of state can be determined from only two scaling constants Es and ρf. thod we present has advantages over previous methods in that Es is state independent, and it can be used to simplify the application to mixtures. That is, only two (rather than three) scaling constants Es and ρf of the mixture components are combined. On the other hand, Es involves the surface entropy and thus, TEs∗ turns out to represent a real thermodynamic quantity that is of concern in theoretical investigations. The applications to the compressed and vapor-saturated liquids of wide range of acentric factors and their mixtures result in densities within less than 5% of the experimental values.