钛氧化物结构及其拉曼光谱表征

Structure and Raman Spectra of Titanium Oxides

采用密度泛函理论(DFT),对几种钛的氧化物晶体结构进行了几何构型优化,得到了与X-ray晶体衍射实验结果相一致的结构参数。在优化几何构型基础上进行了分子振动模的分析和计算,钛氧化物均采用数字化基组和局域密度近似,并选择vwn对局域交换相关能量参数化,使用自旋非限制函数。同时,测定了钛的氧化物(TiO,Ti2O3,Ti3O5,锐钛矿型TiO2和金红石型TiO2)几种晶体的拉曼光谱,并分别解释了相关的拉曼活性振动模。结果表明计算的频率与实验结果比较一致,理论计算频率可以指导实验谱图谱峰位置的归属分析。通过钛的一系列氧化物的常温拉曼光谱分析,得知不同氧化物有不同特征峰,有利于含钛氧化物材料类型的诊断,为沟通结构和性能的相互关系奠定基础。

Under the first-principle density functional theory, structures of several titanium oxides （TiO, Ti2O3, Ti3O5, anatase and rutile） were optimized, and the obtained the structure parameter that coincides with the X-ray crystal diffraction result. The optimized structure parameters coincide well with those obtained by X-ray diffraction method. Molecular vibrational modes were also studied and assigned. Double Numeric including D-polarization function basis set was used with local density approximation, and the local exchange-correlation energy was described with Vosko-Wilk-Nusair and spin non-restricted function. The calculated vibrational wavenumbers were used to interpret observed experimental Raman spectra of those titanium oxides. By comparing the Raman spectra of those titanium oxides with the calculated results, the characteristic peaks of various titanium oxides could be assigned. So the types of titanium oxides could be diagnosed and recognized. This will help to investigate the correlation between the structure and property of materials.