Ion chemistry in octafluorocyclobutane, c-C4F8

Cross-sections for electron impact ionization of octafluorocyclobutane (c-C4F8) have been measured from 10 to 200 eV by Fourier transform mass spectrometry. No parent ion is observed, and over half of the dissociative ionization yields C2F4+ and C3F5+. Eleven other fluorocarbon cations are produced with smaller cross-sections, giving a total ionization cross-section of (1.6±0.2)×10−15 cm2 between 80 and 200 eV. Only CF2+ and C2F3+ react further with the parent molecule to yield C3F5+ as the primary product. No evidence of cationic polymerization was found. F− and C4F8− are formed by electron attachment at energies below 10 eV, but neither reacts further with c-C4F8.