The Reaction of Sulfur Dioxide Radical Cation with Hydrogen and its Relevance in Solar Geoengineering Models |
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| Authors: | Dr. Mauro Satta Dr. Antonella Cartoni Dr. Daniele Catone Dr. Mattea Carmen Castrovilli Dr. Paola Bolognesi Dr. Nicola Zema Dr. Lorenzo Avaldi |
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| Affiliation: | 1. ISMN (CNR) c/o Dipartimento di Chimica Sapienza Universita' di Roma, Pl.e Aldo Moro 5, Roma, Italy;2. Dipartimento di Chimica, Sapienza Universitá di Roma, Pl.e Aldo Moro 5, Roma, Italy;3. CNR-ISM, Area della Ricerca di Tor Vergata, Via del Fosso del Cavaliere, Roma, Italy;4. CNR-ISM, Area della Ricerca di Roma 1, Via Salaria Km 29,300, Monterotondo Scalo (RM), Italy |
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| Abstract: | SO2 has been proposed in solar geoengineering as a precursor of H2SO4 aerosol, a cooling agent active in the stratosphere to contrast climate change. Atmospheric ionization sources can ionize SO2 into excited states of  , which quickly reacts with trace gases in the stratosphere. In this work we explore the reaction of  with  excited by tunable synchrotron radiation, leading to  ( ), where H contributes to O3 depletion and OH formation. Density Functional Theory and Variational Transition State Theory have been used to investigate the dynamics of the title barrierless and exothermic reaction. The present results suggest that solar geoengineering models should test the reactivity of  with major trace gases in the stratosphere, such as H2 since this is a relevant channel for the OH formation during the nighttime when there is not OH production by sunlight. OH oxides SO2, triggering the chemical reactions leading to H2SO4 aerosol. |
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| Keywords: | ion-molecule reactions rate coefficient reaction mechanisms synchrotron radiation VTST |
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