COMMON BULK MODULUS POINT FOR COMPRESSED LIQUIDS

Almost all liquids show a number of simple regularities, such as rectilinear diameters, linear p-T isochores, and linear Zeno contours. Another regularity, recently discovered by Huang and O'Connell, is a common intersection point for the isotherms of the reduced bulk modulus of a compressed liquid as a function of density. A theoretical analysis of this empirical regularity is presented in terms of a statistical-mechanical equation of state. The analysis indicates the limits of validity of the regularity, and shows what molecular characteristics of the liquid are revealed by the location of the common intersection point. The crucial feature is the precise temperature dependence of an equivalent van der Waals covolume, and the location of the point yields direct information on molecular size and shape.