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dc.contributor.authorMarcotte, Guillaumefr
dc.contributor.authorMarchand, Patrickfr
dc.contributor.authorPronovost, Stéphaniefr
dc.contributor.authorAyotte, Patrickfr
dc.contributor.otherLaffon, Carinefr
dc.contributor.otherParent, Philippefr
dc.date.accessioned2015-05-20T19:46:02Z
dc.date.available2015-05-20T19:46:02Z
dc.date.created2015fr
dc.date.issued2015-05-20
dc.identifier.urihttp://hdl.handle.net/11143/6830
dc.description.abstractHeterogeneous nitrates photolysis is the trigger for many chemical processes occurring in the polar boundary layer and is widely believed to occur in a quasi-liquid layer (QLL) at the surface of ice. The dipole forbidden character of the electronic transition relevant to boundary layer atmospheric chemistry and the small photolysis/photoproducts quantum yields in ice (and in water) may confer a significant enhancement and interfacial specificity to this important photochemical reaction at the surface of ice. Using amorphous solid water films at cryogenic temperatures as models for the disordered interstitial air/ice interface within the snowpack suppresses the diffusive uptake kinetics thereby prolonging the residence time of nitrate anions at the surface of ice. This approach allows their slow heterogeneous photolysis kinetics to be studied providing the first direct evidence that nitrates adsorbed onto the first molecular layer at the surface of ice are photolyzed more effectively than those dissolved within the bulk. Vibrational spectroscopy allows the ~3-fold enhancement in photolysis rates to be correlated with the nitrates’ distorted intramolecular geometry thereby hinting at the role played by the greater chemical heterogeneity in their solvation environment at the surface of ice than in the bulk. A simple 1D kinetic model suggests 1-that a 3(6)-fold enhancement in photolysis rate for nitrates adsorbed onto the ice surface could increase the photochemical NO[subscript 2] emissions from a 5(8) nm thick photochemically active interfacial layer by 30%(60)%, and 2-that 25%(40%) of the NO[subscript 2] photochemical emissions to the snowpack interstitial air are released from the top-most molecularly thin surface layer on ice. These findings may provide a new paradigm for heterogeneous (photo)chemistry at temperatures below those required for a QLL to form at the ice surface.fr
dc.language.isoengfr
dc.relation.isformatofDOI: 10.1021/jp511173wfr
dc.relation.ispartofISSN:1520-5215fr
dc.relation.ispartofThe Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theoryfr
dc.subjectChimie atmosphérique hétérogènefr
dc.subjectIce surface (photo)chemistryfr
dc.subjectHeterogeneous nitrate photolysisfr
dc.subjectPhotochemical NO[subscript x] fluxesfr
dc.subjectSnowpack and polar boundary layer chemistryfr
dc.titleSurface-Enhanced Nitrate Photolysis on Icefr
dc.typeArticlefr
udes.description.typestatusPrépublicationfr
udes.description.typepubRévisé et accepté par des pairsfr
udes.description.pages1996-2005fr
udes.description.period119 (10)fr
udes.description.sponsorshipCRSNGfr
udes.description.sponsorshipCPCFQfr
udes.description.diffusionDiffusé par Savoirs UdeS, le dépôt institutionnel de l'Université de Sherbrookefr
dc.identifier.bibliographicCitationGuillaume Marcotte, Patrick Marchand, Stéphanie Pronovost, Patrick Ayotte, Carine Laffon, and Philippe Parent, J. Phys. Chem. A, 2015, 119 (10), pp 1996–2005fr
udes.description.sourceThe Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theoryfr
udes.autorisation.depottruefr
udes.description.ordreauteursMarcotte, Guillaume; Marchand, Patrick; Pronovost, Stéphanie; Ayotte, Patrick; Laffon, Carine; Parent, Philippe


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