不同压力下Ⅰ型甲烷水合物拉曼光谱  

Raman spectra of structure I methane hydrate under different pressures.

作　　者：伍向阳[1,2] 段体玉[3,4] 杨伟[1] 孙樯[3] 

机构地区：[1]中国科学院地质与地球物理研究所地球介质高温高压物理性质实验室,北京100029 [2]中国科学院广州天然气水合物研究中心,广州510640 [3]北京大学地球与空间科学学院地球化学研究所,北京100859 [4]国家首饰质量监督检验中心,北京100101

出　　处：《岩石学报》2008年第1期171-175,共5页Acta Petrologica Sinica

基　　金：中国科学院知识创新工程重要方向项目(KZCX3-SW-224);国家自然科学基金项目(10299041和40074033)资助

摘　　要：本文描述了合成的Ⅰ型甲烷水合物高压下拉曼光谱测定结果。甲烷水合物用细粒冰和甲烷气在温度0℃～9℃和压力18MPa下历时2天合成,在金刚石压腔里进行了原位的显微观察和拉曼光谱测定。一组温度25℃和压力范围132～901MPa下的拉曼光谱数据显示,样品的光谱呈左高右低的双峰结构,左谱峰位置范围为2904.4～2907.2cm^(-1),右谱峰位置范围为2915～2922cm^(-1),谱峰位置随压力变化,典型光谱的左右谱峰强度比近似为3:1,系典型的Ⅰ型结构特征;这说明甲烷水合物在较高压力下也能保持Ⅰ型结构。作为比较,甲烷气和溶解水中的甲烷的拉曼光谱也进行了测定,它们的拉曼光谱特征与Ⅰ型甲烷水合物的明显不同。We report on a set of Raman spectra of structure I methane hydrates under pressures of 132 - 901MPa and 25℃. Methane hydrate samples were synthesized with small granular ices as ＇ seed＇ and pure methane, under a pressure of 18 MPa and changing temperature from 0℃to 9℃： for about 2 days. The samples were observed with microscopy and in situ measured with Raman Spectroscopy in a diamond anvil cell . The result showed that the Raman spectra of samples were doublets with left peak positions of 2904.4 -2907.2cm-1 and right peak positions of 2915 - 2922cm-1. shifted to higher wavenumbers with increasing pressures. The typical intensity ratio of the doublets was about 3 ： 1, which is as characteristics of structure I. That means that methane hydrate can maintain structure I up to a high pressure. Also Ramam spectra for methane dissolved in water and methane in gas phase were measured under a pressure of about 170MPa and 25℃, which were obviously different to the Raman spectra of structure I methane hydrate samples.

关 键 词：Ⅰ型甲烷水合物 拉曼光谱 高压 

分 类 号：P593[天文地球—地球化学]