用K边缘X射线吸收光谱和时间依赖密度函数理论确定的d和f元素金属二二的共价趋势
Stosh A Kozimor1, Ping Yang, Enrique R Batista
1Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Journal of the American Chemical Society
|August 27, 2009
概括
这项研究使用X射线吸收光谱和DFT来比较金属-键中的轨道混合,以寻找过渡金属和活性化物. 显示了过渡元素的约一半的共价轨道混合.
科学领域:
- 无机化学 无机化学 有机化学
- 量子化学 是一个量子化学.
- 材料科学 材料科学 材料科学
背景情况:
- 了解金属素键中的轨道混合对于预测化学反应性和性质至关重要.
- 在类似的结构图案中,对d和f元素进行直接的实验比较是有限的.
- 临界边缘X射线吸收光谱 (XAS) 提供了对电子结构和共价性的敏感探测器.
研究的目的:
- 探测电子结构并确定一系列d和f元素的M-Cl键中的轨道混合程度.
- 为了比较过渡金属 (Ti,Zr,Hf) 和活性化物 (Th,U) 之间的轨道混合趋势.
- 应用和验证混合密度函数理论 (DFT) 计算来解释实验XAS数据.
主要方法:
- 对 (C(5) Me(5)) ((2) MCl(2) 化合物 (M = Ti,Zr,Hf,Th,U) 进行了Cl K边缘X射线吸收光谱 (XAS).
- 使用基态和时间依赖的混合密度函数理论 (DFT) 计算.
- 在DFT计算中使用了相对有效的核心潜力,以准确确定电子结构.
主要成果:
- 通过过渡金属的Cl K-边缘XAS中的前边缘特征观察到共价M-Cl轨道混合的实验证据.
- M-Cl 键中的 Cl 3p 特性数量随着 Ti,Zr 和 Hf 主量子数的增加而略有下降.
- 与研究过渡金属化合物相比, (U) 的共价轨道混合率大约为一半.
结论:
- Cl K-edge XAS 是一种强大的技术,用于研究电子结构和轨道混合在行为系统.
- 在M-Cl键中轨道混合显示了d和f元素之间明显的趋势,其中的活性化物表现出减少的共价性.
- 这项研究为过渡金属和活性化物之间的化学结合差异提供了宝贵的见解.
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