Theory of the liquid state

Considerable progress towards developing satisfactory theories of the liquid state has been made in the past few years. Following a brief discussion of molecular interactions, we review, for simple liquids, four approaches in which there have been recent developments. These are machine calculation methods, the significant structure, Percus‐Yevick, and perturbation theories. The Percus‐Yevick theory does not appear to be useful for real fluids with attractive forces. However, we include this approach because it works very well for hard spheres. This review concludes with a brief discussion of quantum simple liquids and non‐simple liquids. Copyright © 1969 John Wiley & Sons, Inc.