Hyperfine Interaction of Electron at Oxygen Vacancy with Nearest and Next-Nearest ²⁹Si in High-Pressure-Phase SiO_2: Stishovite

Abstract

X- and Q-band electron spin resonance (ESR) studies were performed ona radiation-induced defect in stishovite synthesized under highpressure from high-purity SiO₂ glass, followed by γ-rayirradiation using a source of ⁶⁰Co at room temperature. An oxygenvacancy center which traps an electron (E' center) has an anisotropicg-factor of orthorhombic symmetry, g_x=2.0055, g_y=2.0044 andg_z=2.0023, an axial hyperfine structure due to ²⁹Si (I=1/2), A_x=A_y=1.2 mT and A_z=8.5 mT, and an almost isotropicsuperhyperfine structure due to the second-nearest ²⁹Si, A_shf=1.2 mT.