Interacting hard-sphere fluids in an external field

We present a new method for studying equilibrium properties of interacting fluids in an arbitrary external field. The fluid is composed monodisperse spherical particles with hard-core repulsion and additional interactions shape limited range. Our analysis exact one dimension provides demonstrably good approximations higher dimensions. It can cope homogeneous heterogeneous environments. derive equation the pair distribution function. solution, to be evaluated numerically, general, or analytically special cases, enters expressions entropy free energy functionals. For some one-dimensional systems, our approach yields analytic solutions, reproducing available results from different approaches.