石英拉曼峰进行压力标定的误差研究

Study on the Accuracy of Pressure Determined by Raman Spectra of Quartz

在常温常压下进行了作为压标的石英颗粒的拉曼光谱测量和研究。研究结果发现,在25℃和常压条件下,不同的石英颗粒测得的Si—O振动模在463.59～464.65cm-1范围内变化,误差为(±0.1～±0.3)cm-1。其中不同石英颗粒拉曼峰的最大差异达1.06cm-1,远远大于其测量误差。我们认为这是由于石英破碎时使石英颗粒内产生的应力所致。因此,在进行金刚石压腔高温高压实验的压力确定时,必须以常压下实测的Si—O振动模测量值为零压参考点。另外,拉曼光谱仪的波数漂移以及环境温度的不稳定均会造成不可忽视的压力测量误差,应对此进行校正。

Quartz as a pressure gauge and its accuracy were studied by Raman spectroscopy at 25 ℃ and ambient pressure.The result shows that even at same temperature and pressure,the Si—O vibrational mode[1,2] for different grains of quartz varies between 463.59 and 464.65 cm-1,with （±0.1-±0.3）cm-1 error.The maximum difference of various grains of quartz is up to 1.06 cm-1,much higher than the measurement error.The authors believe that the variety is resulted from the stress in the internal grains of quartz,which formed during crushing quartz into small grain.Therefore,Raman spectrum for quartz has to be firstly measured as a reference of zero pressure at ambient pressure and temperature in the experimental study by using diamond anvil cell.In addition,wavenumber drift of the spectrometer and the unstable temperature will also cause remarkable error for measuring pressure.