Photochemistry of the Mars Atmosphere

VIII-2.1 The Earth s Atmosphere, 330 VIII-2.2 Atmospheric Air Pollution, 332 VIII-2.3 Photochemical Air Pollution in the Troposphere, 332 VIFI-2.4 Air Pollution in the Stratosphere, 340 VI11-3 Photochemistry of the Atmospheres of Other Planets, 352 VH1—3.1 Photochemistry of the Mars Atmosphere, 352 VII 1—3,2 Photochemistry of the Venus Atmosphere. 356 VIIl-3.3 Photochemistry of the Jovian Atmosphere, 357... 

The photochemistry of the Mars and Venus atmospheres may be Ixih, understood if the minor constituents, such as H202, 03, and H2, can I.. measured and if the rate constants involving H02 and ClOO radicals >.m be measured more accurately in the laboratory. McElroy et al. (678) bclm, that CO and H20 are converted to C02 and H2 in the hot region neai tin surface... 

Mumma and Disanti have observed H2O, CO, and HDO in the atmosphere of Mars using both the NICMOS and SBRC detector arrays. These observations were made to understand the effects of odd hydrogen and the D/H ratio on the photochemistry of the Martian atmosphere. 

The recent advances in modem technology continue to open new opportunities for the observation of chemical reactions on shorter and shorter time scales, at higher and higher quantum numbers, in larger and larger molecules, as well as in complex media, in particular, of biological relevance. As an example of open questions, the most rapid reactions of atmospheric molecules like carbon dioxide, ozone, and water, which occur on a time scale of just a few femtoseconds, still remain to be explored. Another example is the photochemistry of the atmospheres of nearby planets like Mars and Venus or of the giant planets and their satellites, which can help us to understand better the climatic evolution of our own planet. 

The recent space probes have stimulated the laboratory experiments. the photochemistry of the constituent gases present in the atmospheres. . Mars, Venus, and Jupiter. Based on these experiments and on the resulr.. 1 recent space probes a number of atmospheric models have been present, i... 

Krasnopolsky V. A. (1986) Photochemistry of the Atmospheres of Mars and Venus. Springer, Berlin. 

The three peaks observed at 1474, 1332, and 1119 A arc assigned by Winter et al. (1052) to the A , Tl and Z states, respectively, onatheoreti-cal basis. Recently the measurement has been extended beyond 1700 A [Ogawa (755), Hcimcrl (461), Shcmansky (871)] as the importance of the photochemistry of C02 in the lower atmosphere of Mars and Venus has been recognized. 

Much of the current interest in the photochemistry of gaseous CO2 is due to its presence as the principal constituent of the atmospheres of Mars and Venus. While laboratory studies continue to confirm its efficient photodecomposition and inefficient recombination, neither ground-based or planetary-mission spectroscopy reveal appreciable concentrations of either CO or O2. Thus it is toward a resolution of these apparently incompatible results that much recent work has been directed. 

CC 2 The photodissociation of CO2 has been the subject of an enormous number of studies, partly for the sake of pure research and partly because of its importance as a planetary atmospheric constituent, especially of Mars. The literature up to the end of 1974 has been exhaustively reviewed by Filseth but since that time a number of significant publications have helped to clarify some of the mysteries that clouded understanding of the molecular photochemistry. 

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