An accurate integral equation for molecular fluids

Abstract

Percus-Yevick (PY), hypernetted chain (HNC) and modified Verlet (VM) integral equation theories are used to study the structure and thermodynamic properties of hard prolate ellipsoids of revolution in the isotropic fluid region. Results for the spherical harmonic coefficients of the pair distribution function and for the compressibility factors are compared with new Monte Carlo results reported in this work for length-to-breadth ratios a/b = 2, 3, and 5. For a/b = 2 and 3, the VM harmonic coefficients are in good agreement with the simulation results and are better than those of PY and HNC theories. For a/b = 5, HNC theory gives numerically precise harmonic coefficients, the VM results being only slightly inferior, a behaviour consistent with that found previously for very long spherocylinders. VM theory gives equation of state results in excellent agreement with the simulation data at all values of a/b and densities, whereas the PY and HNC results are generally poor. The thermodynamic consistency of each...