Theory of Helium Dissolution in Uranium Dioxide. I. Interatomic Forces in Uranium Dioxide

Abstract

Knowledge of the nature of the interatomic forces in uranium dioxide is required for theoretical treatment of phenomena such as radiation damage, adsorption, and gas solubility. The van der Waals and repulsive forces are of particular interest, for these interactions govern the behavior of neutral species in the crystal. The Kirkwood—Müller expression for the coefficients of the 1/rn dispersion forces were employed, and the form of the repulsive potentials was taken from the delta-function model of Mason and Vanderslice. The two disposable parameters in the repulsive potentials were evaluated from data on the atomic properties of the constituent ions and the lattice constant and compressibility of UO2. The calculated cohesive energy of the UO2 lattice was in very good agreement with the value obtained from a conventional Born—Haber cycle.