A new approximate bridge function for pure fluids

The integral equation theory is used to investigate the structural and thermodynamic properties of the Lennard-Jones fluid with a new approximate bridge function, which is based on the modification of its expansion in powers of the thermal potential. The thermodynamic consistency is achieved via the virial and compressibility routes. The problem of the renormalization of the indirect correlation function is also considered with an original prescription for partitioning the pair potential. The bridge function as well as the excess chemical potential and the excess entropy, which are calculated by means of standard formulas of statistical mechanics, are compared to simulation data. The thermodynamic properties of the supercritical Lennard-Jones fluid calculated with the present closure relation are in excellent agreement with those obtained from computer simulation.