Electron attachment and positive ion chemistry of monohydrogenated fluorocarbon radicals
Abstract
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 a kinetic modeling approach. Reaction of the HFC radicals with Ar+ proceeds at or near the calculated collisional rate coefficient in all cases, yielding a wide variety of product ions.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 20, 2015
- Source ID
- 10.1063/1.4928691
Entities
People
- Albert A Viggiano
- Justin P. Wiens
- Nicholas S Shuman
- Thomas M Miller
Organizations
- Air Force Office of Scientific Research
- Air Force Research Laboratory