Search

Theoretical aspects of the MSXα method are analyzed. It is shown that real field self-consistency is not achieved in an MSXα calculation and some consequences of this fact are discussed. The approximations involved in the use of the transition-state procedure to evaluate ionization and excitation energies from a MSXα calculation are presented in some detail and commented.

The SCF-MSXα method is applied in the study of the electronic structure of F centers in CaF2, SrF2, and BaF2. The predicted optical transition energies are in disagreement with the experimental data. An explanation for the discrepancy is provided showing the inadequacy of the spherical averaging of the potential within the muffin-tin approximation. La methode SCF-MSXα a ete utilisee pour la determination de la structure electronique des centres F dans CaF2, SrF2 et BaF2. Les energies calculees pour les transitions optiques sont en desaccord avec les resultats experimentaux. Une interpretation de ce desaccord a ete fournie montrant que la moyenne spherique du potentiel dans l'approximation “muffin-tin” n'est pas adequate en ce cas.