INFRARED ABSORPTION CROSS SECTIONS AND BAND STRENGTHS OF HFC-32 VAPOUR (DIFLUOROMETHANE)
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Date
1996
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
Recent, legislation controlling the use Chlorofluorocarbons (CFCs) has led to the introduction of replacement compounds, hydrochlorofluorocarbons (HCFCs), in a wide range of domestic and industrial applications. However from 2030 the usage of HCFCs will also be controlled and the more environmentally acceptable Hydrofluorocarbons (HFCs) will probably replace them. The C-H bonds present in HCFCs and HCFs allows destruction in the atmosphere by reaction with OH radicals significantly reducing the lifetime of these compounds compared with CFCs. However, many HCFC and HFC compounds absorb strongly in the mid-infrared, particularly in the 8-12$\mu$m ""atmospheric transmission window"" region. It is therefore important to include data on these absorptions in the radiative transfer calculations used to model warming of the Earth#### atmosphere. Medium resolution ($0.03 cm^{-1}$) Fourier Transform Infrared Spectroscopy was used to determine absorbance cross-sections and integrated band strengths of the ro-vibrational absorption bands of HFC-32 lying in the region 600 to $1900 cm^{-1}$. Measurements were performed at eight temperatures (203, 212, 222, 243, 253, 264, 287 and 297 K) for pure vapour samples, and at three temperatures (203, 253 and 297 K) for mixtures containining 5, 20 and 100 kPa of dry air. The derived absorbance cross-section have been submitted for inclusion in the AFGL HITRAN database, and are available via the anonymous FTP site at The University of Stratheclyde (kashmir.phys.strath. ac.uk).
Description
Author Institution: Department of Physics and Applied Physics, Strathclyde University; Atmospheric science division, Space science Department, Rutherford Appleton Laborator; Atmospheric science division, Space science Department, Rutherford Appleton Laborator; Department of Physics and Applied Physics, Strathclyde University; Atmospheric science division, Space science Department, Rutherford Appleton Laborator