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Raman Scattering Study on Vibrational Modes and Structure of Lanthanum Tellurite Glasses
Angelos G. Kalampounias*
Author NameAffiliationE-mail
Angelos G. Kalampounias* Department of Chemical Engineering, University of Patras and Institute of Chemical Engineering and High Temperature Chemical Processes, FORTH/ICE-HT, P.O. Box 1414, Patras, GR-26 504, Greece angelos@chemeng.upatras.gr 
Abstract:
Raman spectra of xLa2O3-(1-x)的TeO2(x=0、0.05、0.10、0.15、0.20和0.25) lanthanum tellurite glasses were measured and analyzed over the entire glass-forming region in an effort to quantitatively follow the structural changes caused by lanthanum oxide variation. For the first time, systematic intensity measurements have been performed to elucidate the composition induced structural changes in the high-frequency stretching vibration region and a possible mechanism was proposed. The network structure of the glasses is formed by mixing TeO4 trigonal bipyramid and TeO3 trigonal pyramid units. The change of the lanthanum oxide content results in conversion of the TeO4 units to TeO3 units with a varying number of non-bridging oxygen atoms. Analysis of the Raman band contours in terms of vibrations due to different oxygen bridged trigonal bipyramid and trigonal pyramid tellurite structural units, allowed to calculate the relative amounts of the species involved in the structural changes with composition. The fraction of the terminal oxygen atoms has been estimated from the Raman intensities with the aid of a structural model concerning the structure of tellurite network systems. The simulation of the experimental density of lanthanum tellurite glasses with modifier content up to 25% revealed that the short range order building units assumed here are sufficient to account for the overall structure in these glasses.
Key words:  Tellurite glass, Raman spectroscopy, Short-range order, Density model
FundProject:
镧碲酸盐玻璃的振动模式和结构的拉曼散射
Angelos G. Kalampounias*
摘要:
利用拉曼光谱研究xLa2O3-(1-x)的TeO2(x=0、0.05、0.10、0.15、0.20和0.25)镧碲酸盐玻璃,并对镧碲酸盐玻璃形成过程中氧化镧变化引起的结构变化进行了分析. 强度测量表明,在高频的伸缩振动区域,组合物被诱导发生结构变化. 通过混合TeO4三角双锥和TeO3三角金字塔单元形成网络结构的镧碲酸盐玻璃. 改变氧化镧的含量导致TeO4单元向含有不同数目的非桥氧原子的TeO3单元转换.通过不同的氧桥三角双锥和三角金字塔碲酸盐结构单元的振动拉曼谱带轮廓分析计算出发生结构变化的组合物的相对量. 另外,通过拉曼强度和与碲酸盐网络结构有关的结构估算出末端氧原子的比例. 对改性剂含量高达25%的镧碲酸盐玻璃的模拟结果表明,短程有序的单元足以构建整个玻璃.
关键词:  碲酸盐玻璃,拉曼光谱,短程有序,密度模型
DOI:10.1088/1674-0068/25/05/519-525
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