The unified picture for the classical laws of Batschinski and the   rectilinear diameter for molecular fluids
  The explicit relations between the thermodynamic functions of the Lattice Gas model and the fluid within the framework of approach proposed earlier in [V. L. Kulinskii, J. Phys. Chem. B \textbf{114} 2852 (2010)] are derived. It is shown that the Widom line serves as the natural border between the gas-like and the liquid-like states of the fluid. The explanation of the global cubic form of the binodal for the molecular liquids is proposed and the estimate for the amplitude of the binodal opening is obtained. 
Leonid A. Bulavin and Vladimir L. Kulinskii
cond-mat.soft cond-mat.stat-mech