Photocatalytic Production of Organic Compounds from CO and H(2)O in a Simulated Martian Atmosphere.
[(14)C]CO(2) and [(14)C]organic compounds are formed when a mixture of [(14)C]CO and water vapor diluted in [(12)C]CO(2) or N(2) is irradiated with ultraviolet light in the presence of soil or pulverized vycor substratum. The [(14)C]CO(2) is recoverable from the gas phase, the [(14)C]organic products from the substratum. Three organic products have been tentatively identified as formaldehyde, acetaldehyde, and glycolic acid. The relative yields of [(14)C]CO(2) and [(14)C]organics are wavelength- and surface-dependent. Conversion of CO to CO(2) occurs primarily at wavelengths shorter than 2000 A, apparently involves the photolysis of water, and is inhibited by increasing amounts of vycor substratum. Organic formation occurs over a broad spectral ranger below 3000 A and increases with increasing amounts of substratum. It is suggested that organic synthesis results from adsorption of CO and H(2)O on surfaces, with excitation of one or both molecules occurring at wavelengths longer than those absorbed by the free gases. This process may occur on Mars and may have been important on the primitive earth.
Space Sciences Division, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, Calif. 91103.
J S
JS
Hubbard
J P
JP
Hardy
N H
NH
Horowitz