Absolute cross sections and kinetic energy release for doubly and triply charged fragments produced by electron impact on CO+

Abstract

Absolute cross sections for electron impact ionization of CO+ leading to the formation of doubly and triply charged products (CO2+, C2+ and O2+, C3+ and O3+) are reported in the energy range from their respective thresholds to 2500 eV. Around the maximum, cross section values are found to be (13.36 ± 0.56) × 10−18 cm2, (5.58 ± 0.55) × 10−18 cm2 and (1.37 ± 0.14) × 10−18 cm2 for CO2+, C2+ and O2+, respectively, and (28.3 ± 7.0) × 10−21 cm2 and (2.4 ± 0.7) × 10−21 cm2 for C3+ and O3+, respectively. The analysis of ionic product velocity distributions, obtained by means of a crossed electron–ion beam set-up, allows the determination of the kinetic energy release distributions. They are seen to extend from 0 to 50 eV both for C2+ and O2+. The mean kinetic energy releases for C3+ and O3+ are found to be 33 ± 5 eV and 39 ± 9 eV, respectively. The cross sections are seen to depend exponentially on the potential energy of each dissociated ion pair. The total single CO+ ionization cross section calculated by application of the Deutsch–Märk (DM) formalism is found to be in good agreement with the experimental results.