Wang Min, You Jinglin, Sobol Alexander, Lu Liming, Wang Jian, Xie Yingfang
State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China.
Prokhorov General Physics Institute, Russian Academy of Sciences, Ulitsa, Vavilova 38, Moscow 119991, Russia.
Materials (Basel). 2017 Mar 17;10(3):310. doi: 10.3390/ma10030310.
Recent interest in optimizing composition and synthesis conditions of functional crystals, and the further exploration of new possible candidates for tunable solid-state lasers, has led to significant research on compounds in this family MM(MO₄)₂ (M = alkali metal, M = Al, In, Sc, Fe, Bi, lanthanide; M = Mo, W). The vibrational modes, structure transformation, and Al coordination of crystalline, glassy, and molten states of KAl(MoO₄)₂ have been investigated by in-situ high temperature Raman scattering and Al magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy, together with first principles density functional simulation of room temperature Raman spectrum. The results showed that, under the present fast quenching conditions, Al is present predominantly in [AlO₆] octahedra in both KAl(MoO₄)₂ glass and melt, with the tetrahedrally coordinated Al being minor at approximately 2.7%. The effect of K⁺, from ordered arrangement in the crystal to random distribution in the melt, on the local chemical environment of Al, was also revealed. The distribution and quantitative analysis of different Al coordination subspecies are final discussed and found to be dependent on the thermal history of the glass samples.
近期，人们对优化功能晶体的组成和合成条件，以及进一步探索可调谐固态激光器的新候选材料产生了浓厚兴趣，这引发了对MM(MO₄)₂（M = 碱金属，M = Al、In、Sc、Fe、Bi、镧系元素；M = Mo、W）这类化合物的大量研究。通过原位高温拉曼散射和铝魔角旋转核磁共振（MAS NMR）光谱，结合室温拉曼光谱的第一性原理密度泛函模拟，对KAl(MoO₄)₂晶体、玻璃态和熔融态的振动模式、结构转变及铝配位情况进行了研究。结果表明，在当前的快速淬火条件下，在KAl(MoO₄)₂玻璃和熔体中，铝主要以[AlO₆]八面体形式存在，四面体配位的铝含量较少，约为2.7%。还揭示了钾离子从晶体中的有序排列到熔体中的随机分布对铝局部化学环境的影响。最后讨论了不同铝配位亚类的分布和定量分析，发现其取决于玻璃样品的热历史。
