Reactions between Vacancies and Impurities in Magnesium Oxide. II. Mn4+-Ion and OH−-Ion Impurities

Abstract

Reactions between cation vacancies and Mn⁴⁺‐ and OH⁻‐ion impurities in MgO are studied as a function of temperature using optical techniques to determine the concentrations of reaction components. The emission spectrum of the Mn⁴⁺ ion in both cubic and noncubic sites in single crystals of MgO is reported, and several new features of the OH⁻‐ion absorption spectrum are discussed. The experiments have enabled the identification of the spectral lines due to Mn⁴⁺ and OH⁻ in isolated and associated sites. Calculation of the OH⁻‐ion eigenfrequencies for ions in various sites, using a point‐charge model, are found to be in good agreement with the experimental results. Finally, observations of the x‐ray‐induced V′ center (the Seitz V₁ center) absorption are found to be consistent with the results of impurity‐ion—vacancy interaction.