Integrated absorption coefficients of CHClF2 (HCFC-22) and CH3Br in the atmospheric infrared window region

Abstract

The integrated absorption coefficients of CHClF₂ have been measured using two different experimental systems. Firstly, low concentration measurements were made using a low resolution FTIR spectrometer with a multipass cell (sample pressures down to 10^4̄ mbar), and secondly, measurements were made over a range of resolutions between 0.75 and 0.004 cm⁻¹ using a high resolution FTIR instrument, but with a shorter pathlength cell and higher sample pressures. The results show no significant variation in the measured integrated absorption coefficients over the concentration range studied or over the range of resolutions used for total pressures between 20 and 500 mbar. The measured values confirm the results of three other studies. Also reported here are integrated absorption coefficients for CH₃Br which are in line with earlier measurements.