Wang Jian, You Jinglin, Wang Min, Lu Liming, Wan Songming, Sobol A A
State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China.
State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2017 Oct 5;185:188-196. doi: 10.1016/j.saa.2017.05.046. Epub 2017 May 23.
In-situ high temperature Raman spectroscopic (HTRS) technique in combination with density functional theory (DFT) analysis has been adopted to investigate the micro-structure of solid and molten AWO (A=Li, Na, K). The [WO] octahedra were found to be connected to each other by corner and edge sharing in the crystalline LiWO and KWO compounds. In the crystal lattice of NaWO, on the other hand, the [WO] tetrahedra and [WO] octahedra were found to coexist and paired by corner sharing. Although the structural diversity has clearly led to distinct Raman spectra of the crystalline AWO compounds, the spectra of their melts tended to be analogous, showing the typical vibration modes of (WO) dimer. A mechanism was then proposed to explain the structure evolution occurring during the melting process of AWO. The effect of A cation on the Raman bands of (WO) dimer in molten AWO has also been investigated. Both the wavenumber and full width at half-height (FWHH) of the characteristic band assigned to the symmetrical stretching vibration mode of WO (non-bridging oxygen) in (WO) were found to decrease in the sequence of Li, Na and K, indicating the cation effect on the mean bond length and its distribution range of WO. In addition, the relative intensity of this band was also influenced by the cation and it was increased in the order of LiWO, NaWO and KWO, which has been explained by the charge transfer process and confirmed by Mulliken overlap population analysis.
采用原位高温拉曼光谱（HTRS）技术结合密度泛函理论（DFT）分析，研究了固态和熔融态AWO（A = Li、Na、K）的微观结构。研究发现，在晶体LiWO和KWO化合物中，[WO]八面体通过角共享和边共享相互连接。另一方面，在NaWO的晶格中，发现[WO]四面体和[WO]八面体共存并通过角共享配对。尽管结构多样性明显导致了晶体AWO化合物具有不同的拉曼光谱，但其熔体的光谱趋于相似，呈现出（WO）二聚体的典型振动模式。随后提出了一种机制来解释AWO熔化过程中发生的结构演变。还研究了A阳离子对熔融AWO中（WO）二聚体拉曼谱带的影响。发现（WO）中归属于WO（非桥氧）对称伸缩振动模式的特征谱带的波数和半高宽（FWHH）按Li、Na和K的顺序降低，表明阳离子对WO的平均键长及其分布范围有影响。此外，该谱带的相对强度也受阳离子影响，其按LiWO、NaWO和KWO的顺序增加，这已通过电荷转移过程得到解释，并通过穆利肯重叠布居分析得到证实。
