TRIPLET DIRECT CORRELATION-FUNCTIONS IN THE HARD-SPHERE FLUID

The weighted density approximation (WDA) to the Helmholtz free energy of an inhomogeneous liquid is used as a generating functional for the triplet direct correlation function c(3) (k,k′) of the hard-sphere fluid. The results are compared to a recent Monte Carlo determination of c(3) for hard spheres and good agreement is found. The WDA results are slightly inferior to those obtained by the free energy model of Rosenfeld, although the WDA predicts the existence of a hard sphere face-centered-cubic (fcc) crystal phase at high densities while the model of Rosenfeld does not. © 1990 American Institute of Physics.