Kinetic energies of ions produced by dissociative electron impact ionization of propane

H. U. Poll, V. Grill, S. Matt, N. Abramzon, K. Becker, P. Scheier, T. D. Märk

Research output: Contribution to journalArticle

Abstract

Mass spectrometric techniques in conjunction with the ion deflection method have been used to measure kinetic energy spectra of the various ions produced by electron-impact ionization and dissociative ionization of propane, C3H8. The kinetic energy spectra of the C3H+i ions (i = 0-8) indicate that these ions are almost exclusively formed with quasithermal energies and that the mechanism of their formation is dominated by the removal of one or more neutral H and H2 fragments accompanied in some cases by a molecular rearrangement of the residual fragment ion. The spectra of the C2H+i fragment ions (i = 0-5) show, besides a quasithermal peak, also ions with higher kinetic energies indicating that a fraction of the ions are the result of processes favoring the formation of energetic, nonthermal fragment ions. Although the quasithermal contribution is dominant in the spectra of the C2H+5 and C2H+4 fragment ions, the spectra of the smaller C2H+i ions (i = 0-3) show a dominance of energetic, nonthermal ions whose formation most likely proceeds via the initial excitation of high-lying repulsive target states. The spectra of the CH+i fragment ions (i = 1-3) are dominated by the presence of energetic, nonthermal ions with kinetic energies of up to 4 eV per fragment ion with quasithermal ions accounting for only about 15% or less of the total ion signal.

Original languageEnglish (US)
Pages (from-to)143-154
Number of pages12
JournalInternational Journal of Mass Spectrometry
Volume177
Issue number2-3
DOIs
StatePublished - Sep 21 1998

Keywords

  • Electron ionization
  • Fragment ions
  • Kinetic energy
  • Propane

ASJC Scopus subject areas

  • Instrumentation
  • Condensed Matter Physics
  • Spectroscopy
  • Physical and Theoretical Chemistry

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