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dc.rights.license© ESO, 2010es
dc.contributor.authorMuñoz Caro, G. M.es
dc.contributor.authorJiménez Escobar, A.es
dc.contributor.authorMartín Gago, J. A.es
dc.contributor.authorRogero, Celiaes
dc.contributor.authorAtienza, C.es
dc.contributor.authorPuertas, S.es
dc.contributor.authorSobrado, J. M.es
dc.contributor.authorTorres Redondo, J.es
dc.date.accessioned2024-02-12T09:39:29Z-
dc.date.available2024-02-12T09:39:29Z-
dc.date.issued2010-11-09-
dc.identifier.citationAstronomy and Astrophysics 522: A108 (2010)es
dc.identifier.issn0004-6361-
dc.identifier.otherhttps://www.aanda.org/articles/aa/full_html/2010/14/aa12462-09/aa12462-09.htmles
dc.identifier.urihttp://hdl.handle.net/20.500.12666/933-
dc.descriptionKey words: ISM: clouds / ISM: molecules / molecular processes / methods: laboratory / infrared: ISM / techniques: spectroscopic ORCID: Sobrado, J. M: 0000-0002-7359-0262es
dc.description.abstractAims. We present the novel InterStellar Astrochemistry Chamber (ISAC), designed for studying solids (ice mantles, organics, and silicates) in interstellar and circumstellar environments: characterizing their physico-chemical properties and monitoring their evolution as caused by (i) vacuum-UV irradiation; (ii) cosmic ray irradiation; and (iii) thermal processing. Experimental study of thermal and photodesorption of the CO ice reported here simulates the freeze-out and desorption of CO on grains, providing new information on these processes. Methods. ISAC is an UHV set-up, with base pressure down to P = 2.5 × 10-11 mbar, where an ice layer is deposited at 7 K and can be UV-irradiated. The evolution of the solid sample was monitored by in situ transmittance FTIR spectroscopy, while the volatile species were monitored by QMS. Results. The UHV conditions of ISAC allow experiments under extremely clean conditions. Transmittance FTIR spectroscopy coupled to QMS proved to be ideal for in situ monitoring of ice processes that include radiation and thermal annealing. Thermal desorption of CO starting at 15 K, induced by the release of H2 from the CO ice, was observed. We measured the photodesorption yield of CO ice per incident photon at 7, 8, and 15 K, respectively yielding 6.4 ± 0.5 × 10-2, 5.4 ± 0.5 × 10-2, and 3.5 ± 0.5 × 10-2 CO molecules photon (7.3–10.5 eV)-1. Our value of the photodesorption yield of CO ice at 15 K is about one order of magnitude higher than the previous estimate. We confirmed that the photodesorption yield is constant during irradiation and independent of the ice thickness. Only below ~ 5 monolayers ice thickness the photodesorption rate decreases, which suggests that only the UV photons absorbed in the top 5 monolayers led to photodesorption. The measured CO photodesorption quantum yield at 7 K per absorbed photon in the top 5 monolayers is 3.4 molecules photon-1. Conclusions. Experimental values were used as input for a simple model of a quiescent cloud interior. Photodesorption seems to explain the observations of CO in the gas phase for densities below 3–7  × 104 cm-3. For the same density of a cloud, 3 × 104 cm-3, thermal desorption of CO is not triggered until T = 14.5 K. This has important implications for CO ice mantle build up in dark clouds.es
dc.description.sponsorship"This work was supported by project AYA2008-06374 funded by Spanish MICINN."es
dc.language.isoenges
dc.publisherEDP Sciencees
dc.rightsAttribution-NonCommercial-NoDerivatives 4.0 Internationales
dc.rights.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/es
dc.subjectISM: cloudses
dc.subjectISM: moleculeses
dc.subjectMolecular processeses
dc.subjectMethods: laboratoryes
dc.subjectInfrared: ISMes
dc.subjectTechniques: spectroscopices
dc.titleNew results on thermal and photodesorption of CO ice using the novel InterStellar Astrochemistry Chamber (ISAC)es
dc.typeinfo:eu-repo/semantics/articlees
dc.identifier.doi10.1051/0004-6361/200912462-
dc.identifier.e-issn1432-0746-
dc.contributor.funderMinisterio de Ciencia e Innovación (MICINN)es
dc.contributor.funderInstituto Nacional de Técnica Aeroespacial (INTA)es
dc.description.peerreviewedPeerreviewes
dc.type.hasVersioninfo:eu-repo/semantics/publishedVersiones
dc.rights.accessRightsinfo:eu-repo/semantics/openAccesses
dc.type.coarhttp://purl.org/coar/resource_type/c_6501es
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