Structure factor and direct correlation function for a classical hard sphere fluid

Abstract

Calculations are reported here of the structure factor S(k) and the direct correlation function C(k) = 1 - S -1 for a classical hard sphere fluid. Exact results are presented to order of the cube in the density ρ and are compared with the results of the various approximate theories, namely the Born-Green, the Percus-Yevick, and the hyperchain. The results have the general character of the observed scattering from liquid argon, though some corrections are required to account for the form of the interaction beyond the hard core.