Condensation of the Lennard-Jones fluid on the basis of the Gibbs single-phase approach.

An accurate expression for the cluster expansion of the configuration integral has been considered based on the Gibbs single-phase approach without additional assumptions and approximations. The computational results for the Lennard-Jones fluid demonstrate the beginning of the condensation process at the singularity points of the isothermal compressibility. It has also been shown that the accuracy boundary of the virial equation of state corresponds to these points, not the virial series singularities. At the high density regime, the inappropriate behavior of the cluster expansion has been discovered that may be related to the infinite limits of the cluster integrals, i.e., their independency on the density.