  The structural properties of square-shoulder fluids are derived from the use
of the rational function approximation method. The computation of both the
radial distribution function and the static structure factor involves mostly
analytical steps, requiring only the numerical solution of a single
transcendental equation. The comparison with available simulation data and with
numerical solutions of the Percus-Yevick and hypernetted-chain integral
equations shows that the present approximation represents an improvement over
the Percus-Yevick theory for this system and a reasonable compromise between
accuracy and simplicity.
