DIFFERENTIAL APPROACH TO THE THEORY OF FLUIDS IN THE PRESENCE OF 2-BODY AND 3-BODY POTENTIALS AND STUDY OF THE CRITICAL-POINT OF KRYPTON

We show how the differential approach to the theory of fluids which gi ves a unified treatment of dense fluids and critical phenomena can be extended to the case of an interatomic interaction of the pair plus tr iplet form. In previously proposed hierarchical reference theory-optim ized random phase approximation the effect of three-body forces is inc luded as a modification of the properties of the reference system and in this calculation these properties are evaluated in modified hyperne tted chain theory. We study the properties of krypton at temperatures greater than the critical temperature and we determine the critical po int of this system with a model potential including an accurate two-bo dy interaction and a three-body contribution of the Axilrod-Teller for m. We study also thermodynamical properties and correlation functions of this system and make a comparison with the available experimental a nd simulation results.