Reaction of the CF3 Radical with Various Cations (Ar+, Xe+, O2 +, NO+, CO2 +, C2F5 +)

Abstract

Abstract The kinetics of reactions of the trifluoromethyl radical (CF3) with several simple cations (Ar+, Xe+, O2 +, NO+, CO2 +, C2F5 +) are studied via the variable electron and neutral density attachment mass spectrometry (VENDAMS) technique. CF3 is produced via dissociative electron attachment to CF3I, resulting in radical concentrations that are smaller than produced using pyrolysis methods, but better quantified. Rate constants and product branching fractions are reported, with typical uncertainties of ∼ 30%. Three of the reactions, Ar+, O2 +, and C2F5 + proceed near the calculated collisional rate constant, while the other reactions are between 10% – 30% efficient. The inefficiency of the reactions of Xe+ and CO2 + can be explained by the reactions strictly obeying spin-conservation. The reaction of Ar+ yields predominantly (90%) CF2 + via dissociative charge transfer, with a minor channel to CF3 +. The reaction of C2F5 + yields predominantly CF3 + with a second channel (∼ 25%) yielding C2F4 + and CF4, the only example here of a bond-breaking and bond-making reaction. For the other four reactions, only charge transfer to yield CF3 + is observed. Rate constants for these same ions with CF3I are also reported and found to be rapid with a variety of products formed.