Partial ionization cross-sections of C2F6

The dissociative ionization of perfluoroethane, C2F6, by electron impact ha s been measured under single-collision conditions using Fourier transform m ass spectrometry. The total ionization cross-section rises to a maximum val ue of 8.9 +/- 1.3 x 10(-16) cm(2) at 70 eV. CF3+ is the most prominent ion fragment at all energies, followed by C2F5+, CF+, and CF2+. C(2)F(6)(+)f is not observed. The ratio of dissociative ionization to total dissociation i ncreases from 27 +/- 5% at 22 eV to 89 +/- 11% at 70 eV. The total cross-se ction and the partitioning among the dissociative channels is examined in t he context of the binary encounter Bethe (BEB) molecular orbital model. (C) 1999 Elsevier Science B.V. All rights reserved.