磁性缺陷中心位于MgO表面. 一个替代氧气空缺的替代模型
Davide Ricci1, Cristiana Di Valentin, Gianfranco Pacchioni
1Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Istituto Nazionale per la Fisica della Materia, Via R. Cozzi, Italy.
Journal of the American Chemical Society
|January 16, 2003
概括
我们提出了一种新的模型,用于MgO表面上的磁性色中心 (F(S) ((H) ((+)) 确定特定的吸附点. 这些发现解释了对这些表面缺陷的实验观测.
科学领域:
- 表面科学是一门科学.
- 材料科学是一种材料科学.
- 固态化学 固态化学
背景情况:
- 磁性颜色中心,特别是F (S) (H) (+) 中心,是氧化 (MgO) 表面上发现的缺陷.
- 这些中心通常通过将MgO暴露在气中,然后进行紫外线照射来形成.
研究的目的:
- 提出一种新的结构模型,用于MgO表面上的F{\displaystyle F} ,S{\displaystyle H} ,H{\displaystyle H} ,+{\displaystyle F} 的磁性色中心.
- 调查特定的表面位点,如步骤边缘和反转角位点在这些中心的形成和特性中的作用.
主要方法:
- 嵌入式集群计算被用于建模拟中心的结构和属性.
- 该研究分析了H2在表面位置的解离,振动频率和电子过渡.
主要成果:
- 在没有反应障碍的逆角 (MgO(RC)) 位点中,H2异质解离,形成MgO(RC) ((H+) ((H-).
- 复合物MgO的计算振动频率与实验数据一致.
- 紫外线诱导的H原子脱附会产生稳定的磁性中心 (MgO (((步) ((H+)) ((e-) 和 MgO ((RC) (((H+)) ((e-)) 与实验观测相一致.
结论:
- 拟议的模型,涉及到步骤边缘和反转角位的吸附,成功地解释了F (S) (H) (+) 中心的特征.
- 这些已识别的中心与氧气空缺缺陷不同,代表了F (S) (H) (+) 缺陷的各种形式.
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