Alexandre Zanchet*, Jia Lei Chen-Qiu, Pascal Larregaray, Laurent Bonnet, Claire Romanzin, Nicolas Solem, Roland Thissen and Christian Alcaraz,
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引用次数: 0
Abstract
Endothermic reactions such as S+(4S) + H2 are not expected to play a significant role in the chemistry of the interstellar medium (ISM). However, in some specific environments, such as photon-dominated regions (PDR), UV radiation may catalyze the reaction by providing enough internal energy to reactants to overcome endothermicity. For instance, it was recently shown that the vibrational excitation of H2 greatly enhances the reactivity of C+ and S+ with H2, explaining the presence of their respective hydrides CH+ and SH+ in these regions. However, vibrational excitation of H2 is not a unique way to enhance the reactivity by UV radiation. Electronic excitation is an alternative way to effectively inject a huge amount of internal energy into the system, thus favoring reactivity. In this work, we will address how electronic excitation of the sulfur cation can strongly enhance the production of SH+. This is done by measuring experimentally the cross section of the title reaction for collision energies from 50 meV up to several eV and comparing the results with theoretical predictions in the 0.001–3 eV range. The reaction cross section is then used to derive the rate constant for a wide range of temperatures.
期刊介绍:
The scope of ACS Earth and Space Chemistry includes the application of analytical, experimental and theoretical chemistry to investigate research questions relevant to the Earth and Space. The journal encompasses the highly interdisciplinary nature of research in this area, while emphasizing chemistry and chemical research tools as the unifying theme. The journal publishes broadly in the domains of high- and low-temperature geochemistry, atmospheric chemistry, marine chemistry, planetary chemistry, astrochemistry, and analytical geochemistry. ACS Earth and Space Chemistry publishes Articles, Letters, Reviews, and Features to provide flexible formats to readily communicate all aspects of research in these fields.