The Formation Energy of Point Defects in Ionic Crystals

Abstract

Simple calculations have been made of the formation energy of different types of defect centres such as those formed by hexavalent uranium introduced into lithium fluoride in an oxygen atmosphere. The Coulomb energies are compared for different configurations of the same defects. The method of calculation is described and results quoted for configurations including, in addition to oxygen ions, (a) a uranium ion and a divalent positive ion, (b) a uranium ion and a negative-ion vacancy and (c) two uranium ions.