Cluster expansion of the distribution functions for a ground state Fermi system

Abstract

The spin-averaged Slater sum of the fermion system is expanded in terms of the square of the ground state wavefunction of a boson system and the "antisymmetry" Ursell function. This expansion is used to obtain the cluster series for the radial distribution function of the fermion system in terms off (-script c sign(n)/S ), where script c sign(n) is sum of chains of (-f/S) and (-fh2B/S) bonds. The series is further expressed in a more compact form using a function L(n) defined by Eq. (55), and the "modified" FHNC approximation for the radial distribution function is presented. © 1983 American Institute of Physics.