光谱学与光谱分析, 2014, 34 (11): 2881, 网络出版: 2014-12-08
2 μm附近CO2谱线参数测量及应用
Measurement and Application of CO2 Spectroscopic Parameters near 2.0 μm
激光吸收光谱 谱线参数测量 同位素丰度 Tunable diode laser absorption spectroscopy Measurement of absorption parameters Isotope abundance
摘要
吸收光谱技术用于痕量气体浓度监测, 特别是在气体分子稳定同位素丰度探测中, 吸收谱线参数的准确性非常重要, 目前普遍使用的HITRAN数据库中给出的各项参数具有一定的不确定性。 为利用2.0 μm激光波段进行CO2浓度及其同位素丰度探测, 需要对该波段的CO2吸收谱线参数进行校准, 采用窄线宽分布反馈式二极管激光器作为光源, 结合自行搭建的谱线参数测量系统, 采集了2.0 μm波段10条CO2吸收谱线, 获得了各谱线的位置、 强度、 自加宽系数和N2加宽系数, 并与HITRAN2012数据库中相应的数据进行对比发现两者之间吻合较好, CO2谱线强度和自加宽系数相对偏差均小于2%。 实测实验室大气的CO2浓度为440 ppm, 13CO2的丰度值δ为-9‰。 测量结果为该波段应用于CO2浓度及13CO2同位素丰度的实时在线探测提供了重要参考依据。
Abstract
The accuracy of absorption spectral parameters is very important for the trace gas measurement based on absorption spectroscopy techniques, especially for the isotopic abundance measurement of gas molecules. For some of the applications, spectral parameters listed in HITRAN database were used to retrieve the trace gas concentration. However, these parameters have uncertainty, in order to validate spectroscopic parameters near 2.0 μm of CO2 lines, which are to be used in detecting the CO2 concentration and isotopic abundance, spectra of those lines were recorded at room temperature using a distributed feed-back (DFB) diode laser. The recorded absorption spectra were fitted to Voigt profile. Line position, intensity, self-broadening coefficient and N2-broadening coefficient were deduced from those data. The results show a good consistency in comparison with those listed in HITRAN2012 database. The discrepancy of most line intensities and self-broadening coefficients are less than 2%. The CO2 concentration and δ(13CO2)in real atmosphere inside laboratory are 440 ppm and -9‰ respectively. These results provide a reliable basis for real time and on line detecting the CO2 concentration and δ(13CO2)in the wavelength range.
孙明国, 马宏亮, 曹振松, 刘强, 王贵师, 陈卫东, 高晓明. 2 μm附近CO2谱线参数测量及应用[J]. 光谱学与光谱分析, 2014, 34(11): 2881. SUN Ming-guo, MA Hong-liang, CAO Zhen-song, LIU Qiang, WANG Gui-shi, CHEN Wei-dong, GAO Xiao-ming. Measurement and Application of CO2 Spectroscopic Parameters near 2.0 μm[J]. Spectroscopy and Spectral Analysis, 2014, 34(11): 2881.