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Infrared spectra of van de Waals complexes of importance in planetary atmospheresIt has been suggested that (CO2)2 and Ar-CO2 are important constituents of the planetary atmospheres of Venus and Mars. Recent results on the laboratory spectroscopy of CO2 containing van der Waals complexes which may be of use in the modeling of the spectra of planetary atmospheres are presented. Sub-Doppler infrared spectra were obtained for (CO2)2, (CO2)3, and rare-gas-CO2 complexes in the vicinity of the CO2 Fermi diad at 2.7 micrometers using a color-center-laser optothermal spectrometer. From the spectroscopic constants the geometries of the complexes have been determined and van der Waals vibrational frequencies have been estimated. The equilibrium configurations are C2h, C3h, and C2v, for (CO2)2, (CO2)3, and the rare-gas-CO2 complexes, respectively. Most of the homogeneous linewidths for the revibrational transitions range from 0.5 to 22 MHz, indicating that predissociation is as much as four orders of magnitude faster than radiative processes for vibrational relaxation in these complexes.
Document ID
19900017433
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Fraser, G. T.
(National Inst. of Standards and Technology Gaithersburg, MD, United States)
Pine, A. S.
(National Inst. of Standards and Technology Gaithersburg, MD, United States)
Lafferty, W. J.
(National Inst. of Standards and Technology Gaithersburg, MD, United States)
Date Acquired
August 14, 2013
Publication Date
May 1, 1990
Publication Information
Publication: NASA, Goddard Space Flight Center, First International Conference on Laboratory Research for Planetary Atmospheres
Subject Category
Lunar And Planetary Exploration
Accession Number
90N26749
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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