Journal of Atmospheric Chemistry 12: 211-227, 1991. 211 © 1991 Kluwer Academic Publishers. Printed in the Netherlands. The Temperature Dependent, Infrared Absorption Cross-Sections for the Chlorofluorocarbons: CFC-11, CFC-12, CFC-13, CFC-14, CFC-22, CFC-113, CFC-114, and CFC-115 ANTHONY H. McDANIEL, CHRIS A. CANTRELL, JAMES A. DAVIDSON, RICHARD E. SHETTER, and JACK G. CALVERT Atmospheric Kinetics and Photochemistry Group, Atmospheric Chemistry Division, National Centerfor Atmospheric Research, P.O. Box 3000, Boulder, CO 80307-3000, U.S.A. Key words: Chlorofluorocarbons, infrared spectroscopy. Abstract. The infrared absorption cross-sections for eight commonly used halogenated methanes and ethanes have been measured as a function of temperature from 203 to 293 K. High resolution spectra (0.03 cm -l) have been used to derive integrated band strengths and peak cross-sections associated with the spectral features in the infrared region from 600 to 1500 cm -2. The values obtained in this study are compared to those from previous reports, and recommendations are made for uses in atmos- pheric sensing and radiative energy transfer models. The observed temperature dependence in the spectral features is also discussed. Key words: Chlorofluorocarbons, infrared spectroscopy. 1. Introduction Chlorofluorocarbons (CFCs) are used extensively as working fluids in industrial applications. This study encompasses eight of the most abundant CFCs measured in the atmosphere. The two most common chlorofluorocarbons, CC13F (CFC-11) and CCI2F 2 (CFC-12), are used as an industrial solvent and in refrigeration, respectively (Rogers and Stephens, 1988). The remaining CFCs, CCIF 3 (CFC-13), CF 4 (CFC-14), CHCIF2 (CFC-22), C2C13F3 (CFC-113), C2C12F4 (CFC-114), and C2CIF 5 (CFC-115) are used as aerosol propellants, working fluids within refrigera- tion systems, foam blowing agents, and solvents (WMO, 1985; Ramanathan et aL, 1985). These manmade compounds, due to their chemical inertness, are useful in a variety of industrial applications; however, it is because of their relative inertness that they may remain in the atmosphere for relatively long time periods and influence stratospheric ozone chemistry and contribute to the 'greenhouse' surface warming of the Earth. Except in the case of CFC-22 which is vulnerable to attack by OH in the troposphere (Ramanathan et al., 1985; Demore et al., 1990), no sig- nificant tropospheric removal mechanism has been identified for these compounds