SPECTRALLY AVERAGED INFRARED ABSORPTION COEFFICIENTS OF CO, HCl, $SO_{2}$ AND $H_{2}S$
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Date
1968
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Ohio State University
Abstract
Spectrally averaged absorption coefficients have been obtained experimentally for $CO, HCl, SO_{2}$, and $H_{2}S$. The average was taken over a *** number interval of $20 cm^{-1}$. Experiments were performed at room temperature by use of *** Elmer 621 grating infrared spectro-photometer with a 10-cm cell and a pressure *** cm Hg. The absorbers were placed in a carrier gas of $CO_{2}$ or nitrogen, and the partial pressures of both absorber and diluent were varied. The data were correlated according to the following expression: $I/I_{***} = \exp[^{-}_{-\alpha}(\rho L)^{n}]$; where L is the path length, p the absorber gas density $= \rho_{o} (P_{i}/P^{o}_{i}), ^{-}_{\alpha}=\alpha_{o}(P_{T}/P^{o}_{T})^{***}$ and $P_{T}$ is a weighted total pressure. $Ladenberg and Reiche^{1}$ have obtained an analytical expression for the average absorption of a Lorentz line, and have shown that the exponent n varies between 0.5 and 1.0. The present data show n to be constant over several decades of absorber gas pressure. Spectrally averaged absorption coefficients are useful in the calculation of overall absorption or emission in gases over a wide frequency range. The gases discussed here may be minor constituents in the atmosphere of Venus. The data will be used to determine what role these gases play in maintaining the high surface temperature of Venus.
Description
This work was supported by NASA Grant NGR 09-015-023. $^{1}$ Ladenberg, R. and Reiche, F. 1913. ``Uber Selektive Absorption'' Ann. Phys. 42, p. 18.
Author Institution: Smithsonian Astrophysical Observatory, Cambridge, Massachusetts and Tufts University; Smithsonian Astrophysical Observatory, and Harvard College Observatory, Cambridge
Author Institution: Smithsonian Astrophysical Observatory, Cambridge, Massachusetts and Tufts University; Smithsonian Astrophysical Observatory, and Harvard College Observatory, Cambridge