STICKY HARD-SPHERES BEYOND THE PERCUS-YEVICK APPROXIMATION

The radial distribution function g(r) of a sticky-hard-sphere fluid is obtained by assuming a rational-function form for a function related to the Laplace transform of rg(r), compatible with the conditions of finite y(r)drop g(r)e(rho(r)/kBT) at contact point and finite isothermal compressibility. In a recent paper [S. Brave Yuste and A. Santos, J. Stat. Phys. 72, 703 (1993)] we have shown that the simplest rational-function approximation, namely, the Pade approximant (2,3), leads to Baxter's exact solution of the Percus-Yevick equation. Here we consider the next approximation, i.e., the Pade approximant (3,4), and determine the two new parameters by imposing the values of y(r) at contact point and of the isothermal compressibility. Comparison with Monte Carlo simulation results shows a significant improvement over the Percus-Yevick approximation.