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# A study of the reactions of trifluoromethyl sulfur pentafluoride, SF5CF3, with several positive ions of atmospheric interest

Atterbury, C. and Kennedy, R. A. and Mayhew, C. A. and Tuckett, R. P. (2001) A study of the reactions of trifluoromethyl sulfur pentafluoride, SF5CF3, with several positive ions of atmospheric interest. Physical Chemistry Chemical Physics, 3 (4). pp. 1949-1953. ISSN 1463-9076

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URL of Published Version: http://dx.doi.org/10.1039/B102504J

Identification Number/DOI: 10.1039/B102504J

An investigation of the bimolecular reactions of several positive ions of atmospheric interest, H$$_3$$O$$^+$$, NO$$^+$$, NO$$_2^+$$, O$$_2^+$$, H$$_2$$O $$^+$$, N$$_2$$O$$^+$$, O$$^+$$, CO$$_2^+$$, CO$$^+$$, N$$^+$$, and N$$_2^+$$, with the greenhouse gas SF$$_5$$CF$$_3$$ is reported. The thermal rate coefficients and ion product distributions have been determined at 300 K using a selected ion flow tube. H$$_3$$O$$^+$$, NO$$_2^+$$, and NO$$^+$$ are found to be unreactive. The reaction with O$$_2^+$$ proceeds with a rate coefficient significantly less than the capture value via chemical routes, in which bonds are broken and formed. The other reagent ions, H$$_2$$O $$^+$$, N$$_2$$O$$^+$$, O$$^+$$, CO$$_2^+$$, CO$$^+$$, N$$^+$$, and N$$_2^+$$ react with SF$$_5$$CF$$_3$$ with reaction rate coefficients close to or at the capture values. With the exception of the reaction with H$$_2$$O$$^+$$, all these efficient reactions occur by dissociative charge transfer, with CF$$_3^+$$ and SF$$_3^+$$ being the dominant product ions. CF$$_3^+$$ forms by direct cleavage of the S-C bond in SF$$_5$$CF$$_3^+$$, and SF$$_3^+$$ probably from dissociation of (SF4+)* following intramolecular rearrangement within the lifetime of (SF$$_5$$CF$$_3^+$$)*. For H$$_2$$O$$^+$$, the observed ion branching ratios suggest that the reaction proceeds via a chemical pathway. The reactions of SF$$_5$$CF$$_3$$ with cations will destroy this molecule in the upper atmosphere.

Type of Work: Article 2001 (Publication) Schools (1998 to 2008) > School of Chemical Sciences School of Chemistry, School of Physics and Astronomy QD ChemistryQC Physics University of Birmingham The authors, Royal Society of Chemistry 671 YES

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