ESR identification of radiation-induced oxygen vacancy centers in paratellurite

The ESR spectrum of paratellurite (α-${\mathrm{TeO}}_2$) 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 ($V_0$(bu) with properties intermediate between those of the $E_1^{\mathcal{’}}$ center in ${\mathrm{SiO}}_2$ and the $F^{+}$ center in alkaline-earth oxides.