Titan interstellar

Yi-Jehng Kuan el al. (2004). Searches for interstellar molecules of potential prebiotic importance. Advances in Space Research 33 31-39 Yung Y., Allen M. and Pinto J. (1984). Photochemistry of the atmosphere of Titan comparison between model and observations. Astronomy Astrophysics Supplement... 

Houdson RL, Moore MH. Reaction of nitriles in ices relevant to Titan, comets and interstellar medium formation of cyanate ion, ketenimines and isonitriles. Icarus 2004, in press. 

C4H2 isomers are of great interest to astronomers because some of these molecules occur in the atmospheres of Titan [74] (and references therein), Jupiter [75] (and references therein), possibly Pluto [76] in a comet [77], and in circumstellar and interstellar media [42,78-80]. Quantum chemical treatments of the 18 possible constructs, which included branched open constructs, produced 10 molecules of which four were open and six were cyclical. All have singlet ground states. Several investigators have synthesized 4Ol(s) in the gas phase and in solvents. Goldberg et al. [81] have synthesized 4O2(s) in the gas phase. 

How can a scientist remain indifferent in light of the fact that carbon chains have been detected by radio astronomers in the molecular clouds present in the interstellar medium or in the circumstellar medium of carbon-rich stars or in the atmosphere of certain bodies of the Solar System such as Titan, Saturn s giant moon The wonder increases further when it is realized that about one thousand organic molecules classified as polyynes are produced by plants, fungi, and microorganisms and play a biological role in the biosphere and may be used in the treatment of diseases as antibiotics, anticancer or, more simply, as anti-infective agents. 

Figure 10.2 Interstellar gas cloud (TITAN s atmosphere) "starting materials" for pre-biotic chemistry, compared with the compounds that result from electrical discharge in an atmosphere of N2 and CH4. Note the extraordinary compatibility between these lists ...

In this chapter, we describe the current status of theoretical kinetics for chemical reactions at low temperature, i.e., from 1 to 200K. The desire to understand the chemistry of interstellar space and of low temperature planetary atmospheres provides the general motivation for studying chemical kinetics at such temperatures. For example, the chemistry of Titan s atmosphere is currently a topic of considerable interest. This motivation led to the development of novel experimental techniques, such as the CRESU (cinetique de reaction en ecoulement supersonique uniforme) method, which allows for the measurement of rate coefficients at temperatures as low as lOK (see Chapter 2 by Canosa et ai). Such measurements provide important tests for theory and have sparked a renewed interest in theoretical analyses for this temperature range. ... 

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