Mixture-Model Approach to the Theory of Classical Fluids

A family of distribution functions is defined for a classical fluid. Interpretation of these distribution functions as mole fractions of quasicomponents suggests that a one-component fluid may rigorously be viewed as a mixture of any number of components. It is suggested that a detailed study of these ``quasicomponent distribution functions'' may be useful in gaining insight into the way an extensive thermodynamic quantity is ``spread'' over the various ``species.'' Some bearings on the existing theories of liquid water are discussed, and it is concluded that the so-called ``continuous'' and ``mixture-model'' approaches to the theory of liquid water are equivalent from the formal point of view.