Infrared absorption cross sections for air-broadened 1,1-dichloro-1-fluoroethane (HCFC-141b)

Abstract

1,1-dichloro-1-fluoroethane (CC12FCH3; HCFC-141b), a hydrochlorofluorocarbon (HCFC) used as a foam blowing agent, a solvent in electronics, and for precision cleaning applications, is currently being phased out under the terms of the Montreal Protocol because it depletes stratospheric ozone. In order to monitor its concentration profiles using infrared-sounding instruments, for example the Atmospheric Chemistry Experiment – Fourier transform spectrometer (ACE-FTS), accurate laboratory spectroscopic data are required. This work describes new high-resolution infrared absorption cross sections of 1,1-dichloro-1-fluoroethane / dry synthetic air over the spectral range 705–1280 cm−1, derived from spectra recorded using a high-resolution Fourier transform spectrometer (Bruker IFS 125HR) and a 26 cm-pathlength cell. Spectra were recorded at resolutions between 0.01 and 0.03 cm−1 (calculated as 0.9/MOPD; MOPD = maximum optical path difference) over a range of temperatures and pressures (7.5–760 Torr and 188–295 K). This new cross-section dataset is the first for air-broadened HCFC-141b over a range of pressures and temperatures appropriate for atmospheric conditions.