Ionization of C3F8 by electron and ion impact

The dissociative ionization of perfluoropropane, C3F8, by electron impact has been measured under single collision conditions using Fourier Transform Mass Spectrometry. The total ionization cross-section rises to a maximum value of 1.24±0.20×10−15 cm2 at 140 eV. CF3+ is the most prominent ion fragment at all energies, followed by C3F7+, CF+, CF2+, C2F4+ and C2F5+; C3F8+ is not observed. The ratio of dissociative ionization to total dissociation increases from 25±8% at 22 eV to no less than 70% from 70 to 200 eV. Among the ion fragments only C3F7+ reacts at room temperature to produce C2F5+.