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Roto-Translational Collision-Induced Absorption of CO2 for the Atmosphere of Venus at Frequencies from 0 to 250 cm(exp -1), at Temperatures from 200 to 800 KThe collision-induced absorption (CIA)of gaseous CO2 is the primary source of far-infrared opacity of the atmosphere of Venus. At the temperatures and densities of the venusian atmosphere, the absorption is due mainly to binary collisions of CO2 molecules. Using a realistic anisotropic intermolecular potential and assuming the absorbing dipole to be due to the electrostatic induction and a quantum overlap, a series of molecular dynamics simulations were performed for the temperature range 200 to 800 K, and the roto-translational (RT) collision-induced absorption spectra at frequencies from 0 to 250 cm(exp -1) were derived. The absorption coefficient in the submillimeter region, used in constituency retrieval studies, decreases more than 10 times in the temperature range 200 to 800 K. On the other hand, the absorption coefficient at 800 K and at the frequency range above 150 cm(exp -1) was found to be almost 10 times higher than at 200 K. Earlier works relied on experimental RT CIA data at a fixed temperature of 300 K. The new, temperature-dependent absorption bands may, when included in the analysis of the atmospheric radiative transfer of the planet, help explain the observed high far-infrared opacity of the lower layers of the atmosphere. To make the results of the simulations readily available for atmospheric abundance and radiative transfer analysis, an analytic model of the roto-translational collision-induced absorption spectral profile, applicable from 200 to 800 K, is being proposed here. The FORTRAN computer code of this newly developed model is available from the authors on request.
Document ID
19990062340
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Gruszka, Marcin
(Michigan Technological Univ. Houghton, MI United States)
Borysow, Aleksandra
(Michigan Technological Univ. Houghton, MI United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1997
Publication Information
Publication: ICARUS
Publisher: Academic Press
Volume: 129
ISSN: 0019-1035
Subject Category
Lunar And Planetary Exploration
Report/Patent Number
IS975773
Funding Number(s)
CONTRACT_GRANT: NAG5-4534
Distribution Limits
Public
Copyright
Other

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