Electron-impact dissociation and ionization of OH+ and OD+ ions

Abstract

Absolute cross sections for electron impact ionization and dissociation of OH+ and OD+ leading to the formation of the OH2+, O+, O2+, O3+ and D+ ions have been measured by applying the animated electron-ion beam method in the energy range from the respective reaction thresholds up to 2.5 keV. The maximum of the single ionization cross section is found to be (0.95±0.02) × 10−19 cm2 at 155 eV. The maximum total cross sections for O+ and D+ fragments production are observed to be (15.7±0.2) × 10−17 cm2 at 95 eV and (10.8±0.5) × 10−17 cm2 at 95 eV, respectively. The cross sections for O2+ and O3+ are much smaller, (5.37±0.04) × 10−18 cm2 at 135 eV and (7.95± 0.23) × 10−20 cm2 at 315 eV, respectively. The collected data are analyzed in details in order to determine separately the contributions of dissociative excitation and of dissociative ionization to the O+ and D+ fragments production.