Electron-nuclear double resonance of theF+center inα-alumina

Electron paramagnetic resonance measurements of fast-neutron-irradiated $\alpha$-alumina show an intense 13-line spectrum which has been previously interpreted by La, Bartram, and Cox (LBC) as due to the $F^{+}$-center defect. Electron-nuclear double resonance (ENDOR) measurements on this center reveal superhyperfine (shf) interactions with neighboring A1 nuclei out to the sixth shell which support this $F^{+}$-center model. The original point-ion calculation of the shf constants performed by LBC is extended to include these more distant shells for comparison with the ENDOR measurements.