温度和压强的变化对谱线线型峰值的影响

Accurate Calculation of Spectral Line Profiles by Considering Influence of Varying Pressure and Temperature in a Gas

谱线线型是用于气体浓度测量中的一个重要参数。本文基于温度(压强)变化会引起相应压强(温度)的变化这一点,考虑温度和压强同时变化对气体线型峰值的影响。通过分析氟化氢的吸收谱线,发现可用Lorentzian线型来计算峰值吸收系数的温度和压强范围都扩大,而Gaussian线型在绝大数情况下不能用来计算峰值吸收系数;在一定的温度范围和压强范围内,如果只考虑压强或温度的变化,由此计算的三种线型峰值(Gaussian,Lorentzian和Voigt)的相对误差大于0.1。因此,在计算线型峰值时,需考虑压强和温度同时变化对线型峰值的影响。最后分别讨论了甲烷、二氧化碳、一氧化碳及一氧化氮,得到与氟化氢结论相似的结论,结论的不完全相同是由于每种气体在波数、压力展宽系数、相对分子质量及温度系数上的不同而导致。

Accurate calculation of spectral line profiles of a gas is very important for gas sensing. As we know, a variation in pressure （temperature） of a gas will result in the corresponding variation in temperature （pressure） of the gas. In the present pa-per we calculated spectral line profiles of a gas by considering the changes in both temperature and pressure. The authors found that in our case the Lorentzian profile has broader applicable ranges of pressure and temperature, and the Gaussian profile is only applicable in some extreme conditions. Furthermore, the authors found that the influence of variations in pressure and tempera- ture has to be considered in calculating the peak values of the spectral line profiles such as Gaussian, Lorentzian, and Voigt; oth-erwise the resultant relative errors of the calculated peak values can exceed 0. 1. The similar observations were also found for other gases such as CH4, CO2, CO, and NO, although the parameters such as wavelength, coefficient of pressure-broadening, relative molecular mass, and temperature were different.