Theory of Color Centers. III. Continuum Models of F₂⁺- and F₂-Centers

Abstract

The F₂⁺- and F₂-centers, the molecule ion and molecule formed from two F-centers, are treated by the variational method developed by R. Kubo. The crystal is supposed to be a continuous medium with dielectric constants κ (static) and κ₀ (optical) and the two negative ion vacancies are considered as point charges. The polarization arising from ionic displacements is supposed to give a fixed field for the electronic motion. The electronic levels are calculated and compared with those obtained by Kubo for the F-center. A rough estimate of the dissociation energies are also given.