Self-consistent molecular field theory for packing in classical liquids.

Building on a quasichemical formulation of solution theory, this paper proposes a self-consistent molecular field theory for packing problems in classical liquids, and tests the theoretical predictions for the excess chemical potential of the hard sphere fluid. Results are given for the self-consistent molecular fields obtained, and for the probabilities of occupancy of a molecular observation volume. For this system, the excess chemical potential predicted is nearly as accurate as the most accurate prior theories, specifically the scaled particle (Percus-Yevick compressibility) theory. A compact formula is obtained to throw light on the variation of the chemical potential with the radius of a distinguished hard sphere solute in general solvents. It is argued that the present approach is particularly simple, permits a natural description of possibilities for multiphasic behavior of the solution, and should provide a basis for a molecular-scale description of more complex solutions.