Electron attachment to F2

The rate constant ka for electron attachment to F2 has been measured at ambient (298 K) temperature T in the buffer gas Ar over the mean electron energy 〈ε〉 range 0.40–2.95 eV; similar measurements were made at T=233, 298, and 373 K in the buffer gas N2 over the 〈ε〉 range 0.04–0.75 eV. The ka(〈ε〉) function attains a maximum value of 1.7×10−8 cm3 s−1 (T=298 K) at ∼0.04 eV and decreases monotonically with increasing 〈ε〉 above thermal energy; the magnitude of ka increases only slightly with increasing T. The ka(〈ε〉) data at 298 K were unfolded and the resultant cross section σa(ε) shows a main maximum at ∼0.0 eV, a shoulder at ∼0.5 eV, and a weak maximum at ∼1.1 eV. Possible electron attachment processes are discussed to account for the energy dependence of σa(ε). Also discussed, in the light of the present measurements, are published experimental and theoretical results on ka(〈ε〉) and σa(ε).