Studies in Molecular Dynamics. VII. Hard‐Sphere Distribution Functions and an Augmented van der Waals Theory

Hard‐sphere radial distribution functions are evaluated in the dense fluid phase and compared to the predictions from various integral equations. Perturbation theory is then used to add various attractive potentials to the hard core in order to demonstrate the near constancy of the van der Waals energy density parameter a. The augmented van der Waals theory which replaces the parameter b by the hard‐sphere equation of state and “a” by its theoretical value is then used to predict the dependence of the critical point on the shape of the intermolecular potential. The critical volume and temperature are found to be sensitively dependent on the range and depth of the intermolecular forces.