F+centres in wurtzite lattices. I. The effects of host lattice covalence

Publisher Website
Google Scholar
Abstract
Principles of calculating the electronic structure of the F+ centre in partially covalent solids are discussed. A bond-orbital model of the perfect lattice is described, and the effects of this covalence on the F+ centre energy levels and hyperfine interactions are investigated. The effective-charge method of treating covalent crystals is critically examined, and rejected in favour of an ionic ion-size model for variational calculations. The covalence is less important in calculating wavefunctions than in using the wavefunctions to derive hyperfine interactions. Lattice distortions give only small changes in transition energies, but are extremely important in determining the hyperfine interactions.