ESR identification of radiation-induced oxygen vacancy centers in paratellurite

The ESR spectrum of paratellurite (α-TeO2) exposed to 1-MeV electron irradiation reveals a single spin-(1/2) defect in eight inequivalent sites with an anisotropic g value close to the free-electron value. Principal g values are 2.0105 +- 0.0005, 1.9705 +- 0.0005, and 1.9358 +- 0.0005. Resolved hyperfine structure is attributed to magnetic isotopes of tellurium in seven different sites neighboring each defect site. The g-value anisotropy together with the hyperfine structure suggest a positively charged, oxygen-vacancy model (V0(bu) with properties intermediate between those of the E1/sup prime/ center in SiO2 and the F+ center in alkaline-earth oxides