CaSiO3从熔体到玻璃的结构和拉曼光谱性质研究

采用分子动力学模拟以及一种计算拉曼谱的新方法研究了CaSiO₃从高温熔体淬火到室温玻璃态的过程中微结构性质和拉曼谱的变化。在结构变化中，主要是键长随温度的降低而缩短，并且Si-O_b键长的下降幅度明显比Si-O_nb的下降幅度大，另外Si-O_b和Si-O_nb两种键的物质的量分数的变化说明温度的降低使体系的无序度降低。随着温度的降低，偏拉曼谱中表征5种Q_i的强特征峰的频率都呈上升趋势，而且基本与温度呈一个直线关系。计算结果还证实，温度对拉曼散射系数没有影响。得到的拉曼散射系数的两个比值分别为：S₃/S₂=0.3987和S₂/S₁=0.4801，与实验值吻合得非常好。

Theoretical Study of Structural and Raman Spectral Properties of CaSiO3 Quenched from Melt to Glass

With the molecular dynamics simulation and a newly method for the Raman spectra calculation, we studied the changes of micro-structural and Raman spectral properties of CaSiO₃under the quenching process from high-temperature melt down to the room-temperature glass. In the structural properties, the Si-O bond is shortened following with the decrease of temperature, and the shortening degree of Si-O_b bond is obviously greater than that of Si-O_nb bond. Meanwhile, the variation of molar fractions of Si-O_b and Si-O_nb bonds indicated that the decrease of temperature reduced the disorder degree of the system. With the decrease of temperature, the characteristic bands of five kinds of tetrahedral units in the partial Raman spectra shifted to the high frequency direct, and a linear relation was found between the frequency and temperature. The calculated results also gave the strong conclusion that the temperature has no effect on the Raman scattering coefficients. Finally, two ratios of Raman scattering coefficients were obtained as follow: S₃/S₂=0.3987 and S₂/S₁=0.4801, which agreed very well with the corresponding experimental values.