Simulation of binary hard-sphere systems with 1 : 5 and 1 : 10 size ratios

Hard-sphere molecular dynamics simulations were performed on asymmetric binary systems to obtain pair-correlation functions. Particle-diameter ratios of 1:5 and 1:10 were applied to mimic the colloid/solvent situation, where the large particles were the colloids and the small ones represented the solvent molecules. The packing fractions were chosen systematically between 0.1-0.5 for the large spheres and 0.0-0.5 for the small ones. We focused on two questions: a) To what extent can one approximate the inter- particle structure of the large spheres in binary systems with one-component hard-sphere data. b) How reliable are the theoretical pair- correlation functions of the Percus- Yevick and Rational Function Approximation models. Overlap integrals of pair- correlation function pairs were calculated to answer quantitatively. The results supported quantitatively the limits of the one-component hard-sphere approximation. On contrary, the selected theoretical methods reproduced the simulation results satisfactorily, if the packing fraction of the solvent was not more than 0.2. The theoretically important contact values of the pair-correlation functions were calculated, too.