在散装MGO中中性F中心的光学属性与密度矩阵嵌入
Shreya Verma1, Abhishek Mitra1, Yu Jin1
1Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States.
The journal of physical chemistry letters
|August 22, 2023
概括
本研究使用先进的计算方法研究了MgO中中性氧空缺. 结果显示,计算的光学光谱与实验数据密切匹配,表明三重-单重衰变路径.
科学领域:
- 固态物理 固态物理
- 计算材料科学科学 计算材料科学
- 量子化学 是一个量子化学.
背景情况:
- 中性氧空缺 (F0中心) 是氧化 (MgO) 晶体中的关键缺陷.
- 了解它们的光学特性是MgO在电子和光学中的应用的关键.
- 以前的研究往往缺乏对这些缺陷状态的高精度理论预测.
研究的目的:
- 为了准确计算F0中心的光学光谱,大量的MgO.
- 将理论预测与实验吸收和排放数据进行比较.
- 阐明所涉及的电子转换和衰变路径.
主要方法:
- 使用密度矩阵嵌入理论 (DMET) 进行缺陷建模.
- 用多参考方法解决杂质哈密尔顿式:完整的活性空间自相一致场 (CASSCF) 和第二阶n电子价值状态扰动理论 (NEVPT2).
- 在非嵌入和热力学极限使用双重推算方案来确定缺陷局部化的垂直激发能量.
主要成果:
- 推断出的NEVPT2-DMET垂直激发能量为5.24 eV,与实验吸收最大值在5.03 eV的极佳一致.
- 对于放松的三重组缺陷局部状态,计算出的2.89 eV的激发能量接近于2.4 eV的实验辐射.
- 这一小小的差异表明,三重-单重衰变途径参与了发光过程.
结论:
- 该理论框架准确地复制了MgO中的F0中心的实验光学光谱.
- 这些发现提供了强有力的证据,证明三重-单重衰变机制控制了发光.
- 这项工作为研究氧化物点缺陷提供了可靠的计算方法.
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