Integral equation theory for uncharged liquids: The Lennard-Jones fluid and the bridge function

For the Lennard-Jones fluid, a new approximation for the bridge function is introduced and tested. The approximation is semi-phenomenological in nature. The structure predicted by the new approximation, in the form of the pair correlation function g(r), agrees extremely well with recent computer simulations for large systems, over the full range of density and temperature. The thermodynamic properties of the Lennard-Jones fluid are predicted and are in better agreement with computer simulations than earlier theories. The gas-liquid phase diagram predicted by this work is displayed and discussed.