Calculation of the entropy for hard-sphere from integral equation method

The Ornstein-Zernike integral equation method has been employed for a single-component hard sphere fluid in terms of the Percus-Yevick (PY) and Martynov-Sarkisov (MS) approximations. Virial equation of state has been computed in both approximations. An excess chemical potential has been calculated with an analytical expression based on correlation functions, and the entropy has been computed with a thermodynamic relation. Calculations have been carried out for a reduced densities of 0.1 to 0.9. It has been shown that the MS approximation gives better values than those from the PY approximation, especially for high densities and presents a reasonable comparison with available data in the literature.Comment: 7 page