Towards an understanding of the structure of molten copper chloride

The authors show that information may be obtained about a linear combination of the short-range forces in molten salts-the short-range ordering potential nu s (r)-by using the ordering-potential analysis which was originally introduced to study liquid semiconductors. This procedure requires a full knowledge of the charge-charge partial structure factor, S QQ (k). In order to fit the small-k behaviour of the experimental neutron data of S QQ (k) in molten CuCl it becomes necessary to introduce partial ionicity in the Coulomb interaction between the ions in the melt and the authors discuss the possible reasons as to why this may be so. They also present the results of calculations of the partial structure factors, S alpha beta (k), of molten CuCl. These are carried out within the mean-spherical approximation using a model of charged spheres, with charge Z=0.16 and a radii ratio of 0.36. The results reproduce the main qualitative features as compared with the neutron diffraction data. Finally they suggest that the apparently unusual features of the S alpha beta (k)s in molten CuCl are likely to be typical of those systems which melt from a superionic phase, such as the copper halides and silver iodide.