Analytical representation of the density derivative of the Percus Yevick hard sphere radial distribution function
ABSTRACT Explicit analytical expressions are presented for the density derivative, gHS(R; r)/r, of the Percus Yevick approximation to the hard sphere radial distribution function for R 6s, where s is the hard sphere diameter and r (N/V)s3 is the reduced density, where N is the number of particles and V is the volume. A FORTRAN program is provided for the implementation of these for R 6s, which includes code for the calculation of gHS(R; r) itself over this range. We also present and incorporate within the program code convenient analytical expressions for the numerical extrapolation of both quantities past R 6s. Our expressions are numerically tested against exact results.