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Franco Cataldo 《Origins of life and evolution of the biosphere》2006,36(5-6):467-475
Carbon vapour generated from a carbon arc or by laser ablation of graphite is reactive with simple molecules and atoms producing
end-capped polyyne chains. With these techniques both hydrogen-terminated polyynes as well as monocyano- and dicyanopolyynes
have been produced. Experiments based on arcing graphite electrodes can reproduce the molecular distribution of polyynes existing
around carbon-rich AGB stars. In fact, it has been found that the relative abundances of the polyynes produced in carbon arc
in vacuum decreases by a factor between 3 and 5 as the chain length increases by a C2 unit. An analogous trend has been observed both for polyynes and cyanopolyynes in the circumstellar environment around carbon-rich
stars. This fact suggests that the mechanism of formation of the polyynes in the carbon arc may be similar to that occurring
in the surroundings of the carbon-rich stars. Polyynes and cyanopolyynes represent authentic prebiotic molecules which appear
quite ubiquitous in the cosmos and should have played a role in the early organic chemistry preceding the appearance of life.
Presented at: National Workshop on Astrobiology: Search for Life in the Solar System, Capri, Italy, 26 to 28 October, 2005. 相似文献
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