Raman Spectra of Carbonate Ions as Pressure Gauge at High Pressure and Room Temperature

在准静水压的条件下,利用碳化硅压腔和显微拉曼光谱原位测量技术,在0～1.7 GPa压力范围测定22℃高压下三种不同的H2O-Na2CO3体系(1.5,2.0,2.5 mol·L-1)中CO32-的对称伸缩振动v1 066拉曼谱峰的变化.结果表明,在室温条件下,碳酸根的v1 066峰的拉曼位移随着压力的增大而线性增加.三种浓度下v1 066峰的拉曼位移与压力的拟合直线彼此接近,斜率误差小于1%,偏差小于系统误差,因此在实验误差范围内碳酸根浓度对v1 066峰随压力变化的行为不存在影响.经过数据拟合得到公式:p/MPa=174.13△v1 066/cm-1-59.03(△v1 066=v1 066-v1 0660,v1 0660为体系零压时碳酸根离子v1 066峰的拉曼位移).此公式可以用于常温下在含有纯碳酸钠体系中的压力标定.Three aqueous solutions of sodium carbonate (1. 5, 2. 0 and 2. 5 mol.L(-1)) were studied by in-situ Raman spectrum in a moissanite anvil cell in order to measure the Raman shift of symmetric stretching vibration of carbonate ion at around nu(1 066). The experiment was conducted from 0 to 1. 7 GPa under quasihydrostatic conditions at temperature of 22 degrees C. The result showed that the increase in Raman wavenumber shift of in-plane bending vibration of carbonate ion is linearly proportional to the rise of pressure under room temperature. At the three concentrations mentioned above, the correlations between Raman shift of the nu(1 066) peak and the pressure are depicted as three nearly identical curves, with a slope error smaller than 1%. The deviation, being smaller than the systemic error, suggested that the concentration of carbonate ions, within experimental errors, has no detectable influence on the pressure- induced shift of nu(1 066) peak. Besides, the data fitting generated the formula: p/MPa = 174. 13 Delta nu(1 066)/cm(-1)-59. 03(Delta(nu 1 066) = nu(1 066) - nu(0)(1 066), where nu(0)(1 066) denotes the Raman shift of nu(1 066) peak of carbonate ion under the ambient pressure, which can be used as a pressure gauge in pure Na(2)CO(3) solution.高等学校博士学科点专项科研基金; 国家自然科学基金http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000263801800026&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701SCI(E)EIPubMed中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)13690-6932