Maximum Entropy Approach to the Theory of Simple Fluids

We explore the use of the method of Maximum Entropy (ME) as a technique to generate approximations. In a first use of the ME method the “exact” canonical probability distribution of a fluid is approximated by that of a fluid of hard spheres; ME is used to select an optimal value of the hard‐sphere diameter. These results coincide with the results obtained using the Bogoliubov variational method. A second more complete use of the ME method leads to a better descritption of the soft‐core nature of the interatomic potential in terms of a statistical mixture of distributions corresponding to hard spheres of different diameters. As an example, the radial distribution function for a Lennard‐Jones fluid (Argon) is compared with results from molecular dynamics simulations. There is a considerable improvement over the results obtained from the Bogoliubov principle.