Investigation of the absorption coefficient of methane in pollution gas measurement

To investigate the absorption coefficient in pollution gas measurement, taking the methane at 2ν3 band R3 manifold as an example, we discuss the absorption coefficient for the Gauss and Lorentz profiles. We prove the normalized line profile of the Gauss and Lorentz profiles, then we discuss the peak absorption coefficients for the Gauss and Lorentz profiles, and average peak absorption coefficient for the Lorentz profile. Some useful conclusions are drawn. This investigation will be significant in pollution gas measurement.