Infrared absorption cross-sections and integrated absorption intensities for difluoromethane (HFC-32) and 1,1,1,2-tetrafluoroethane (HFC-134a) in the 650-50 cm-1 region

High-resolution (0.03 cm(-1)) infrared absorption cross sections and integrated absorption intensities for difluoromethane (HFC-32) and 1,1,1,2-tetrafluoroethane (HFC-134a) are reported for the 50-650 cm(-1) spectral region. The data presented are for the pure vapour and for several mixtures with dry air, at a series of temperatures between ca. 200 K and room temperature. The absorption cross sections were calculated with and without correction for backward or sample emission, and it is shown that this correction can be important. The data are supported by ab initio calculations at a relatively high level of theory. The effect of buffer gas pressure and temperature on the integrated cross sections is discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.