气体红外吸收特性受压强与温度的影响分析

Effects of pressure and temperature on gaseous infrared absorption properties

气体的红外吸收特性是利用红外光学方法对气体进行定性定量分析的重要依据。吸收谱线的峰值吸收系数与全线宽是描述气体红外吸收特性的两个重要参量,参考HITRAN2004数据库,以乙炔在近红外的一段红外光谱为研究对象,对压强与温度对峰值吸收系数与全线宽的影响规律进行了研究,结果表明:当压强大于0.1 MPa时,峰值吸收系数与全线宽随压强的升高而增大,但后者的增长率较前者更大;而当温度在200～400 K范围时,乙炔在6 565～6 595 cm-1范围内的吸收谱线的峰值吸收系数与全线宽随温度的升高而降低,且温度对峰值吸收系数的影响要强于对全线宽的影响。分析结果对于气体的红外光学检测具有重要的工程应用价值。

Gaseous infrared absorption properties are the important basis of qualitative and quantitative analysis by infrared optical methods.The peak absorption coefficient and full width at half maximum value（FWHM） of an absorption line are two valuable parameters for infrared absorption properties.Referring to HITRAN2004 database,the variations of the peak absorption coefficient and FWHM of acetylene near infrared spectrum at the spectral range of 6 565-6 595 cm-1 with pressure and temperature have been researched.The results show that the peak absorption coefficient and FWHM all grow with pressure when the pressure is above 0.1 MPa,and the grow rate of FWHM is bigger than that of the peak absorption coefficient.The peak absorption coefficient and FWHM of the acetylene absorption lines between 6 565 cm-1 and 6 595 cm-1 all decrease with temperature increasing when the temperature is at 200-400 K,and the influence on the peak absorption coefficient is stronger than that on FWHM.The analysis results are valuable references for the infrared gas detection.