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hal.structure.identifierInstitut des Sciences Moléculaires [ISM]
dc.contributor.authorDARANLOT, Julien
hal.structure.identifierAMOR 2012
dc.contributor.authorHINCELIN, U.
hal.structure.identifierInstitut des Sciences Moléculaires [ISM]
dc.contributor.authorBERGEAT, Astrid
hal.structure.identifierInstitut des Sciences Moléculaires [ISM]
dc.contributor.authorCOSTES, Michel
hal.structure.identifierInstitut des Sciences Moléculaires [ISM]
dc.contributor.authorLOISON, Jean-Christophe
hal.structure.identifierAMOR 2012
dc.contributor.authorWAKELAM, Valentine
hal.structure.identifierInstitut des Sciences Moléculaires [ISM]
dc.contributor.authorHICKSON, Kevin M.
dc.date.created2012-06
dc.date.issued2012
dc.identifier.issn0027-8424
dc.description.abstractEnMany chemical models of dense interstellar clouds predict that the majority of gas-phase elemental nitrogen should be present as N2, with an abundance approximately five orders of magnitude less than that of hydrogen. As a homonuclear diatomic molecule, N2 is difficult to detect spectroscopically through infrared or millimeter-wavelength transitions. Therefore, its abundance is often inferred indirectly through its reaction product N2H+. Two main formation mechanisms, each involving two radical-radical reactions, are the source of N2 in such environments. Here we report measurements of the low temperature rate constants for one of these processes, the N + CN reaction, down to 56 K. The measured rate constants for this reaction, and those recently determined for two other reactions implicated in N2 formation, are tested using a gas-grain model employing a critically evaluated chemical network. We show that the amount of interstellar nitrogen present as N2 depends on the competition between its gas-phase formation and the depletion of atomic nitrogen onto grains. As the reactions controlling N2 formation are inefficient, we argue that N2 does not represent the main reservoir species for interstellar nitrogen. Instead, elevated abundances of more labile forms of nitrogen such as NH3 should be present on interstellar ices, promoting the eventual formation of nitrogen-bearing organic molecules.
dc.language.isoen
dc.publisherNational Academy of Sciences
dc.typeArticle de revue
dc.identifier.doi10.1073/pnas.1200017109
dc.subject.halPlanète et Univers [physics]/Astrophysique [astro-ph]/Astrophysique galactique [astro-ph.GA]
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Astrophysique galactique [astro-ph.GA]
dc.identifier.arxiv1206.4905
bordeaux.journalProceedings of the National Academy of Sciences of the United States of America
bordeaux.page10233-10238
bordeaux.volume109
bordeaux.peerReviewedoui
hal.identifierhal-00709160
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00709160v1
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