常温0.1～2GPa压力下文石的拉曼光谱研究

Raman Spectra of Aragonite at the Pressure of 0.1～2 GPa and Ambient Temperature

利用碳化硅压腔结合拉曼光谱分析技术,研究了常温0.1～2GPa压力下文石的拉曼光谱特征,并得出文石拉曼位移与压力之间的关系:ν153(cm-1)=0.0035p(MPa)+154.0,ν206=0.0060p+206.3,ν704=0.0021p+704.2,ν1085=0.0035p+1085.3。在实验的压力范围内,未观察到文石的相变。另外,与其他碳酸盐矿物(菱镁矿、白云石)类似,0～2GPa压力下文石的对称伸缩振动拉曼位移随压力变化的dν1025/dp值大于超高压条件下的dν1025/dp值,表明碳酸盐矿物[CO3]基团中C—O键的可压缩性和压力有关,其可压缩性在0.1～2GPa时较大,压力升高可压缩性降低。

Raman spectra of aragonite were studied at ambient temperature and pressure of 0.1~2 GPa in a moissanite anvil cell using Raman spectrum technique.The relations between the Raman shifts of aragonite and the system pressure are given as follows：ν153（cm-1）=0.003 5p（MPa）＋154.0,ν206=0.006 0p＋206.3,ν704=0.002 1p＋704.2,ν1 085=0.003 5p＋1 085.3.No phase transition occurred in aragonite within the range of experimental pressure.Similar to other carbonate minerals（magnesite,dolomite）,the measured relative pressure-shift of the Raman line of the symmetric stretching vibration of aragonite is greater at 0.1-2 GPa than at ultrahigh pressure,which indicates that the C—O bond compressibility of the CO3 groups is related to the pressure,and it is more compressible at 0.1~2 GPa than at higher pressure.