Electron attachment and positive ion chemistry of monohydrogenated fluorocarbon radicals

Rate coefficients and product branching fractions for electron attachment and for reaction with Ar+ are measured over the temperature range 300–585 K for three monohydrogenated fluorocarbon (HFC) radicals (CF3CHF, CHF2CF2, and CF3CHFCF2), as well as their five closed-shell precursors (1-HC2F4I, 2-HC2F4I, 2-HC2F4Br, 1-HC3F6I, 2-HC3F6Br). Attachment to the HFC radicals is always fairly inefficient (between 0.1% and 10% of the Vogt–Wannier capture rate), but generally faster than attachment to analogous perfluorinated carbon radicals. The primary products in all cases are HF-loss to yield CnFm−1− anions, with only a minor branching to F− product. In all cases the temperature dependences are weak. Attachment to the precursor halocarbons is near the capture rate with a slight negative temperature dependence in all cases except for 2-HC2F4Br, which is ∼10% efficient at 300 K and becomes more efficient, approaching the capture rate at higher temperatures. All attachment kinetics are successfully reproduced using...