1.0～4.4GPa下奥长石拉曼光谱特征的变化  

Variation of Raman Spectra of Oligoclase under 1.0～4.4 GPa

作　　者：谢超[1] 杜建国[1] 崔月菊[1] 陈志[1] 张炜斌[1] 易丽[1] 邓莉[1] 

机构地区：[1]中国地震局地震预测研究所,北京100036

出　　处：《光谱学与光谱分析》2012年第3期691-694,共4页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(40873049;41104052;40904055;41174071);国家科技支撑项目(WFSD-10)资助

摘　　要：常温、1.0～4.4GPa下,利用激光拉曼光谱研究了奥长石晶体结构随压力的变化。发现,压力为2.9GPa时,517cm-1附近出现新的谱峰,奥长石开始相变。3.4GPa时,源于奥长石结构中M—O伸缩振动的288cm-1拉曼谱峰频移发生突变,517cm-1附近谱峰消失,奥长石由三斜晶系完全相变为单斜晶系(P1-I1)。随压力增加,归属于奥长石四面体结构中Si—O—Si弯曲振动的458及516cm-1谱峰随压力增加有规律地向高频方向偏移,斜率分别是1.667cm-1/GPa和3.560cm-1/GPa,而源于Al—O—Al弯曲振动的480cm-1谱峰与压力没有明显的线性变化关系。卸压过程中,288cm-1拉曼谱峰频移保持不变,458,480及516cm-1谱峰向低频偏移。长石类矿物的相变压力与结构中八元环所含阳离子种类有关。Variation of crystal structure of oligoclase with pressure was investigated by the approach of diamond anvil cell（DAC） and in situ micro-Raman spectroscopic measurement at room temperature and under pressures from 1.0 to 4.4 GPa.At 2.9 GPa a new peak round 517 cm-1 appeared,and a new phase was produced.Near 3.4 GPa a major discontinuity occurs in the pressure dependence of 288 cm-1 peak arising from the stretching mode of M—O,and 517 cm-1 peak disappeared,it implied that the oligoclase underwent triclinic to monoclinic phase transition completely at about 3.4 GPa.The peaks at 458 and 516 cm-1 peaks arising from flexural vibrational mode of Si—O—Si shifted linearly with the increasing pressures,the pressure-related slopes are 1.667 cm-1/GPa and 3.560 cm-1/GPa,respectively,whereas,the flexural vibrational mode of Al—O—Al at 480 cm-1 did not shifted linearly with the increasing pressures.The position of 288 cm-1 peak did not change obviously in comparision with 458,516 and 480 cm-1 peaks,which shifted to lower frequency during decompression.The phase transition pressure of feldspar relates to the species of cation in the octatomic rings.

关 键 词：奥长石 拉曼光谱 压力 相变 阳离子 

分 类 号：P574.1[天文地球—矿物学]