常温0～1GPa压力下重晶石的拉曼光谱研究

Raman Spectra Study of Barite at the Pressure of 0～1 GPa and Ambient Temperature

利用碳化硅压腔装置研究了高压下重晶石的S—O对称伸缩振动9ν87和对称弯曲振动4ν52及4ν62的拉曼光谱变化特征。实验结果表明：在常温和0~1 GPa压力范围内重晶石稳定,其拉曼谱峰随压力升高向高波数方向移动,二者的关系表达式分别为：9ν87=0.004 4p＋987.42,4ν52=0.002 3p＋452.6,4ν62=0.001 8p＋462.42,而且伸缩振动受压力的影响比弯曲振动大。重晶石的987 cm-1拉曼谱峰强度约为石英464 cm-1拉曼谱峰的六倍,可作为压腔中良好的压力标定物。实验得到压力与重晶石987 cm-1峰偏移量的关系为：p（MPa）=223.16×（Δpν）987-90.35（987 cm-1〈pν〈992 cm-1）。不同硫酸盐矿物间的d1ν/dp差异反映了[SO4]基团中S—O键的可压缩性及其化学键的强度。

The variation characters of Raman spectra of S—O symmetric stretching vibration ν987 and symmetric bending vibration ν452 and ν462 of barite at high pressure were studied using moissanite anvil cell.The experimental results show that barite is stable at the pressure of 0～1 GPa and ambient temperature,and the Raman peak positions of barite shift to higher frequency with increasing pressure.The relations between the Raman shifts and system pressure are given as follows： ν987=0.004 4p＋987.42,ν452=0.002 3p＋452.6,ν462=0.001 8p＋462.42,and that stretching vibrations are more affected by pressure than bending vibrations. The intensity of 987 cm-1 Raman peak of barite is six times greater than that of 464 cm-1 Raman peak of quartz,so barite can be used as a good pressure gauge.Besides,the relation between the system pressure and Raman shift of 987 cm-1 peak position of barite is given as follows： p（MPa）=223.16×（Δνp）987-90.35（987 cm-1νp992 cm-1）.The difference in the measured relative pressure-shift of the Raman line of the symmetric stretching vibration among various sulfate minerals shows the compressibility and strength of the S—O bond in the SO4 group.