Phase diagram and thermodynamic properties of H₂

A statistical mechanical-based theory is used to develop the equation of state for the molecular fluid of H₂. We incorporate in this equation the long-range correlations through the double Yukawa potential, dimerization of the H₂ molecule by treating the fluid as a hard convex body fluid, and first-order quantum correction which is important at low temperatures. We use this to calculate the liquid-vapor equilibrium of H₂, including the temperature and pressure dependence of compressibility factor, entropy, specific heat, compressibility, and sound velocity.