Spectroscopic fingerprints of valence and spin states in manganese oxides and fluorides
Spectroscopic fingerprints of valence and spin states in manganese oxides and fluorides
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DOI：
10.1016/j.cap.2012.09.017
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发表时间：
2013-05-01
影响因子：
2.4
通讯作者：
Yang, Wanli
中科院分区：
文献类型：
--
作者：
Qiao, Ruimin;Chin, Timothy;Yang, Wanli
我们对各种锰氧化物和氟化物的软X射线吸收光谱进行了系统的研究。Mn的L-边和配体（O和F）的K-边，并相互比较。尽管不同体系的晶体结构和共价/离子性质不同，但Mn-L光谱通过光谱线形和能量位置一致而明显地指纹化Mn的价态和自旋态。在我们的高分辨率光谱中，清晰的O-和F-K前边缘特征使得能够定量定义具有不同Mn价的分子轨道图。另外，O-1 s核电子的结合能差导致三价和四价锰氧化物的O-K前沿发生了小的位移，而二价和三价锰氧化物的O-K前沿发生了明显的位移，且位移的能量要大一个数量级，这是由于半填充3d体系的自旋交换稳定化作用.在离子氟化物体系中，这种位移大大增强。这为进一步研究复杂锰化合物提供了光谱基础。(C)2012 Elsevier B. V.保留所有权利。
We performed a systematic study of soft X-ray absorption spectroscopy in various manganese oxides and fluorides. Both Mn L-edges and ligand (O and F) K-edges are presented and compared with each other. Despite the distinct crystal structure and covalent/ionic nature in different systems, the Mn-L spectra fingerprint the Mn valence and spin states through spectral lineshape and energy position consistently and evidently. The clear O- and F-K pre-edge features in our high resolution spectra enable a quantitative definition of the molecular orbital diagram with different Mn valence. In addition, while the binding energy difference of the O-1s core electrons leads to a small shift of the O-K leading edges between trivalent and quadrivalent manganese oxides, a significant edge shift, with an order of magnitude larger in energy, was found between divalent and trivalent compounds, which is attributed to the spin exchange stabilization of half-filled 3d system. This shift is much enhanced in the ionic fluoride system. This work provides the spectroscopic foundation for further studies of complicated Mn compounds. (C) 2012 Elsevier B.V. All rights reserved.