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Photochemistry of CO and H_2O: Analysis of Laboratory Experiments and Applications to the Prebiotic Earth's Atmosphere

Wen, Jun-Shan and Pinto, Joseph P. and Yung, Yuk L. (1989) Photochemistry of CO and H_2O: Analysis of Laboratory Experiments and Applications to the Prebiotic Earth's Atmosphere. Journal of Geophysical Research D, 94 (D12). pp. 14957-14970. ISSN 0148-0227. doi:10.1029/JD094iD12p14957.

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The role photochemical reactions in the early Earth's atmosphere played in the prebiotic synthesis of simple organic molecules was examined. We have extended an earlier calculation of formaldehyde production rates to more reduced carbon species, such as methanol, methane, and acetaldehyde. We have simulated the experimental results of Bar-Nun and Chang (1983) as an aid in the construction of our photochemical scheme and as a way of validating our model. Our results indicate that some fraction of CO_2 and H_2 present in the primitive atmosphere could have been converted to simple organic molecules. The exact amount is dependent on the partial pressure of CO_2 and H_2 in the atmosphere and on what assumptions are made concerning the shape of the absorption spectra of CO_2 and H_2O. In particular, the results are most sensitive to the presence or absence of absorption at wavelengths longward of 2000 Å. We also find that small quantities of CH_4 could have been present in the prebiotic Earth's atmosphere as the result of the photoreduction of CO.

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Yung, Yuk L.0000-0002-4263-2562
Alternate Title:Photochemistry of CO and H2O: Analysis of Laboratory Experiments and Applications to the Prebiotic Earth's Atmosphere
Additional Information:© 1989 by the American Geophysical Union. Received June 6, 1988; revised February 14, 1989; accepted February 14, 1989. Paper number 89JD00342. This work was partially supported by NASA grant NAGW-1538 to the California Institute of Technology. We thank H. D. Holland for many long and productive discussions and for exerting a benign influence on us over the years. We thank J. F. Kasting and K. J. Zahnle for many stimulating discussions. We also thank two referees for their constructive and useful comments. Contribution number 4570 from the Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena.
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Caltech Division of Geological and Planetary Sciences4570
Issue or Number:D12
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Official Citation:Wen, J.-S., J. P. Pinto, and Y. L. Yung (1989), Photochemistry of CO and H2O: Analysis of laboratory experiments and applications to the prebiotic Earth's atmosphere, J. Geophys. Res., 94(D12), 14957–14970, doi:10.1029/JD094iD12p14957.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:49943
Deposited By: Ruth Sustaita
Deposited On:23 Sep 2014 20:19
Last Modified:10 Nov 2021 18:49

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