The liquid state

Abstract

One of the main difficulties in constructing a theory of liquid structure is the calculation of the entropy, due to the many possible geometrical configurations which the atoms can take up. Recent attempts to solve this problem have been directed to finding simple models capable of reproducing the main features of the liquid state. Some progress has been made by using the concepts of order and disorder, first introduced to explain certain properties of alloys. In this connexion theories of melting are of importance and these are discussed with an indication of their successes and limitations. Another problem of theoretical and practical importance is the determination of the average distribution of atoms in a liquid. Information of this kind can be derived from the study of x-ray diffraction patterns of liquids. Recently, attempts have been made with notable success to calculate distribution functions theoretically from known atomic forces. These have been compared where possible with those derived from experiment, and information has been derived about the number of nearest neighbours and the sizes of the various coordination shells. The significance of observations on viscosity and specific heats of liquids is examined, and reference is made to recent theories of the condensation of gases.