Some theoretical calculations of the physical properties of certain crystals

Abstract

This paper is a continuation of a series of others, recently published, in which an attempt is made to co-ordinate kinetic theory data with crystal data simultaneously to determine interatomic fields. The methods there described are here elaborated and extended, and new considerations are introduced which have the effect of modifying the conclusions previously reached. The repulsive fields of a number of ions are determined and are used to calculate a number of crystal properties, including compressibility and elasticity, which are compared where possible with experiment. The calculations have been made as extensive as possible in order to explore to the full the possibilities of the central field of force and in particular that of the inverse power law. The main features of the preceding papers were (i) the determination from certain gaseous properties of neon and argon of a series of models to represent their interatomic fields ; (ii) the assumption of the equivalence of the repulsive fields of atomic or ionic cores of the same structure ( i . e ., Cl - and K + were assumed equivalent to A); (iii) the unique determination of the fields by a comparison of calculated and observed interatomic distances in the crystals NaF and KCl.