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利用活塞圆筒装置在1.2GPa,1 473K的条件下合成了白硅钙石。采用外加热装置和金刚石压腔结合拉曼光谱分析技术,采集了白硅钙石298,353,463,543,663,773以及873K温度区间的常压及1atm~14.36GPa(常温)压力区间的拉曼谱图。扫描电镜下,该研究合成的样品为结构一致的单一相,颗粒大小为10~20μm。电子探针分析结果表明,样品的组成为Ca7.03(2)Mg0.98(2)Si3.94(2)O16,该组分完全吻合白硅钙石理论组分。Raman分析结果表明,高温时白硅钙石的拉曼谱图中具有29个振动峰。随着温度的升高,部分振动峰出现了合并或者弱化消失的现象。该现象尤其以800~1 200cm-1范围内的909,927和950cm-1振动峰峰位最为明显,这些振动峰分别在873,773以及873K时弱化消失。据此,白硅钙石的结构在实验温压范围内稳定,且随着温度和压力的升高,其拉曼振动峰峰位分别呈现往低频和高频方向线性飘移的趋势。除此之外,根据高温和高压拉曼实验的结果,分别计算了白硅钙石拉曼振动峰峰位的等压mode-Grüneisen参数和等温mode-Grüneisen参数,其算术平均值分别为1.47(2)和0.45(3)。最后结合高温和高压拉曼实验的结果,计算了白硅钙石的非谐系数,结果表明,Si-O振动模式对于非谐效应的贡献要小于其他振动模式。
The use of piston cylinder device at 1.2GPa, 1 473K under the conditions of the synthesis of the silicate stone. A Raman spectroscopy technique was used to measure the Raman spectra of the cesium silicate 298, 353, 463, 533, 663, 773 and 873K at atmospheric pressure and 1atm ~ 14.36GPa (normal temperature). Under the scanning electron microscope, the sample synthesized in this study is a single phase with the same structure and the particle size is 10 ~ 20μm. The results of electron probe analysis showed that the composition of the sample was Ca7.03 (2) Mg0.98 (2) Si3.94 (2) O16, which was in good agreement with the theoretical composition of. The results of Raman analysis show that there are 29 vibrational peaks in the Raman spectrum of the kauriite at high temperature. As the temperature rises, some vibration peaks appear to merge or weaken. This phenomenon is most obvious at 909, 927 and 950 cm-1 in the range of 800 to 1 200 cm-1. These vibrational peaks weaken and disappear at 873, 773 and 873 K, respectively. Accordingly, the structure of the kauriite is stable within the experimental temperature and pressure range, and as the temperature and pressure increase, the peak positions of Raman vibration appear to drift linearly toward the low frequency and the high frequency respectively. In addition, based on the results of Raman experiments at high temperature and high pressure, the isopotential mode-Grüneisen parameters and isothermal modem-Grüneisen parameters of Raman peaks at calcite were calculated, and their arithmetic mean values were 1.47 2) and 0.45 (3). Finally, the results of Raman experiments at high temperature and high pressure were used to calculate the anharmonic coefficient of the silicogasterite. The results show that the contribution of the Si-O vibration mode to the nonharmonic effect is smaller than that of other vibration modes.