R. W. Rozett

Ion–Molecule Reactions of C+ with N2 and O2

Using a tandem mass spectrometer, the reactions C++X2→X2++C →X+X++C →CX++C, where X is either nitrogen or oxygen, were studied in the ion energy range 5–200 eV. By studying the attenuation of the C+ ion beam as a function of N2 pressure at various electron energies, and by measuring the ion–molecule reaction cross sections at different electron energies, it was possible to estimate the contribution of the 2P and 4P states of C+ to the reactions.

Reaction of C+ with CH4 in the 2–200‐eV Energy Range

The reaction of C+(2P) with CH4 has been investigated in the 2–200‐eV energy region using a tandem mass spectrometer. All possible ions containing one or two carbon atoms were observed except C2H4+. The behavior of the cross sections as a function of the kinetic energy of the incident ion was used to infer reaction mechanism. Evidence was obtained for the presence of a complex, stripping and binary collision mechanisms.

Electronic States of H2O+ Produced by Electron Bombardment of H2O

The abundance of the electronic states of H2O+ produced by electron bombardment of H2O vapor in the energy range 12–70 eV have been determined by studying the attenuation of the H2O+ ion beam in nitrous oxide. The ground state (2B1), the first excited state (2A1), and probably the second excited state (2B2) were found to be present, and their abundance was found to be a function of the electron bombarding energy and the water vapor pressure in the ion source.

Collision‐Induced Dissociation on HD+ by Rare Gases

Absolute cross sections and kinetic isotope ratios for the dissociation of MD+ into protons and deuterons when striking helium, neon, argon, krypton, and xenon are reported up to 50‐eV incident kinetic energy. The calibration of the tandem mass spectrometer is described in detail. The spectator mechanism for ion–molecule reactions has been elaborated to account for the periodic maxima observed in the cross sections of these collision‐induced reactions.

Reactions of C+ with Ethane, Ethylene, and Acetylene

The ion‐molecule reactions of C+(2P) with ethane, ethylene, and acetylene in the gas phase have been investigated over a projectile energy ranging from a few to 100 eV. Ions with one, two, and three carbon atoms and a varying number of hydrogen atoms were observed. The behavior of the cross sections as a function of kinetic energy of the incident ion was used to infer reaction mechanism. The energetics of the processes were the most dominant parameters determining the courses of the reactions.

Reactions of C+ Ions with Some Methyl Halides

The reactions of C+ in the ground state with the methyl halides (CH3X) were studied in the 2–200‐eV energy region using a tandem mass spectrometer. The cross sections as a function of ion kinetic energy were measured and used to infer reaction mechanism. Hydride ion, halide ion, carbanion as well as halogen atom and CH3 pickup were dominant reactions at low energy. At higher energies dissociative anion pickup was an important mechanism for the formation of ions containing one carbon atom. The polarizability of the C–X bond and the energetics of the process appeared to be the most important factors dictating the course of the reaction.

Reaction of C+(2P) with CH3F

The ion–molecule reaction C+(2P)+CH3F has been investigated in the 2–200‐eV energy region using a tandem mass spectrometer. All possible ions containing one and two carbon atoms were observed except C2H3F+. The behavior of cross section as a function of the kinetic energy of the incident ion was used to infer reaction mechanism. Hydride ion, fluoride ion, and fluorine atom pickup were the dominant reactions at low energies.