On the Kinetic Theory of Dense Fluids. VI. Singlet Distribution Function for Rigid Spheres with an Attractive Potential

A new integro-differential equation for the singlet distribution function in a model dense fluid is derived and solved. In the model considered, the pair interaction potential is represented as a rigid core plus a soft attraction. Interactions between two rigid cores are handled as in the theory of the dense rigid-sphere fluid, while interactions between the soft attractions are handled, following Kirkwood, in the Fokker-Planck approximation. The use of coarse graining in time to provide a time scale permitting the above separation, the relaxation in momentum space, the kinetic flux vectors, and the physical basis of the analysis are all discussed.