Corundum (α-Al₂O₃) is a technologically important material and, in particular, widely used in optical applications such as luminescent radiation dosimeters, cryogenic scintillators, and is being considered as a promising candidate for windows in future fusion reactors. Its optical and mechanical properties are controlled by the presence of radiation-induced (in particular, by fast neutrons) defects. Herein, the thermal stability and recombination kinetics of primary anion Frenkel defects—the F and F ⁺ electronic centers and oxygen interstitials—in fast-neutron-irradiated α-Al₂O₃ single crystals are analyzed. Theory is developed considering the formation of both neutral and charged oxygen Frenkel defect pairs; defect migration, interaction and recombination. Based on ab initio calculations and new theoretical kinetics analysis, for the first time, a coexistence is demonstrated, in comparable concentrations, of two interstitial types—neutral O atoms and negatively charged O⁻ ions (with attributed optical absorption band maxima at 6.5 eV and 5.6 eV, respectively); and their diffusion parameters, necessary for the prediction of secondary defect-induced reactions and defect/material thermal stability, are obtained.

中文翻译：

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中子辐照刚玉单晶中的两种氧间隙原子：联合实验和理论研究

刚玉 (α-Al ₂ O ₃ ) 是一种技术上重要的材料，特别是广泛用于光学应用，如发光辐射剂量计、低温闪烁体，并且被认为是未来聚变反应堆窗口的有希望的候选材料。其光学和机械性能受辐射诱导（特别是快中子）缺陷的控制。在此，快速中子辐照的 α-Al ₂ O _{3中初级阴离子 Frenkel 缺陷（} F和F ⁺电子中心和氧间隙子）的热稳定性和复合动力学分析单晶。理论的发展考虑了中性和带电氧弗伦克尔缺陷对的形成；缺陷迁移、相互作用和重组。基于从头算计算和新的理论动力学分析，首次证明了在可比浓度下两种间隙类型的共存——中性 O 原子和带负电的 O ^-离子（归因于光学吸收带最大值为 6.5 eV 和分别为 5.6 eV）；以及它们的扩散参数，这些参数对于预测二次缺陷引起的反应和缺陷/材料的热稳定性是必要的。