title: Hydration Leads to Efficient Reactions of the Carbonate Radical Anion with Hydrogen Chloride in the Gas Phase.
abstract: The carbonate radical anion CO3•-is a key intermediate in tropospheric anion chemistry. Despite its radical character, only a small number of reactions have been reported in the literature. Here we investigate the gas-phase reactions of CO3•-and CO3•-(H2O) with HCl under ultrahigh vacuum conditions. Bare CO3•-forms OHCl•-with a rate constant of 4.2 × 10-12cm3s-1, which corresponds to an efficiency of only 0.4%. Hydration accelerates the reaction, and ligand exchange of H2O against HCl proceeds with a rate of 2.7 × 10-10cm3s-1. Quantum chemical calculations reveal that OHCl•-is best described as an OH•hydrogen bonded to Cl-, while the ligand exchange product is Cl-(HCO3•). Under tropospheric conditions, where CO3•-(H2O) is the dominant species, Cl-(HCO3•) is efficiently formed. These reactions must be included in models of tropospheric anion chemistry.
authors.affiliation: Department of Biology and Chemistry, City University of Hong Kong , 83 Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, China.
authors.forename: Wai Kit
authors.initials: WK
authors.lastname: Tang
authors.affiliation: Institut für Ionenphysik und Angewandte Physik, Leopold-Franzens-Universität Innsbruck , Technikerstraße 25, 6020 Innsbruck, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: van der Linde
authors.affiliation: Department of Biology and Chemistry, City University of Hong Kong , 83 Tat Chee Avenue, Kowloon Tong, Hong Kong SAR, China.
authors.forename: Chi-Kit
authors.initials: CK
authors.lastname: Siu
authors.affiliation: Institut für Ionenphysik und Angewandte Physik, Leopold-Franzens-Universität Innsbruck , Technikerstraße 25, 6020 Innsbruck, Austria.
authors.forename: Martin K
authors.identifier: http://orcid.org/0000-0001-9373-9266
authors.initials: MK
authors.lastname: Beyer