The 17O hyperfine structure of trapped holes photo generated at the surface of polycrystalline MgO

Surface trapped hole centers have been generated by X-ray irradiation on an 17O isotope enriched MgO sample. The resulting EPR spectrum allowed us to determine for the first time the complete 17O− hyperfine tensor (A = [18.6, 18.6, −104.8] G). Comparison of the measured data with those obtained by embedded cluster density functional theory calculations allows to identify the hole trapping center with three-coordinated oxide anions localized at MgO corners.