Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Tokyo, 153-8505, Japan.
J Phys Chem B. 2013 Jun 6;117(22):6823-9. doi: 10.1021/jp401730f. Epub 2013 May 23.
Molecular dynamics simulations have been performed to prepare the structural model of BaTi2O5 glass. The total correlation function obtained from the structural model agreed rather well with both the X-ray and neutron diffraction data. We found distorted 4-, 5-, and 6-coordinated Ti atoms whose distortion increases with coordination number. Furthermore, the distorted polyhedra were connected to each other by corner-, edge-, or face-sharing. Using the optimal structural model, the vibrational density of state was calculated, and the origin of the bands of Raman scattering spectrum was investigated. It was revealed that not only symmetric and antisymmetric vibration in one TiOn polyhedron but also stretching, bending, and rocking motions in Ti-O-Ti linkage contributed to the Raman bands above 600 cm(-1), which govern the principal vibration in the glass. These results conclude that a Ti-O-Ti network consisting of various types of TiOn polyhedra certainly exists in BaTi2O5 glass, although the local structure around Ti deviates from the Zachariasen's rule of glass formation.
已经进行了分子动力学模拟，以准备 BaTi2O5 玻璃的结构模型。从结构模型中获得的总相关函数与 X 射线和中子衍射数据非常吻合。我们发现了扭曲的 4、5 和 6 配位 Ti 原子，其扭曲程度随配位数增加而增加。此外，扭曲的多面体通过角共享、边共享或面共享彼此连接。使用最佳结构模型，计算了振动态密度，并研究了拉曼散射光谱带的起源。结果表明，不仅是一个 TiOn 多面体中的对称和反对称振动，而且 Ti-O-Ti 键中的伸缩、弯曲和摇摆运动也对 600 cm(-1) 以上的拉曼带做出了贡献，这些带控制着玻璃中的主要振动。这些结果表明，尽管 Ti 周围的局部结构偏离了玻璃形成的 Zachariasen 规则，但 BaTi2O5 玻璃中确实存在由各种类型的 TiOn 多面体组成的 Ti-O-Ti 网络。
