A Born model calculation of the energies of vacancies, ion interstitials and inert gas atoms in calcium fluoride

The energy of inert gas interstitials and the activation energy for gas diffusion have also been calculated. Values for the binding energy of the gas into vacancies suggest that there may be a slight modification of the diffusion due to gas trapping. All the calculations were performed by minimizing the energy with respect to the displacements and dipoles of ions in a relatively large region (15-20 shells) surrounding the defect. A new numerical method used in the calculation of the relaxation is ten or twenty times faster than conventional minimization methods.