Ionization and dissociation of N2 and CO in collisions with 2.3q-keV Arq+ (8≤q≤14)

The charge-state and energy distribution of molecular ions and fragments produced in low-energy, highly-charged-argon-ion collisions with N2 and CO were measured. Arq+ (8≤q≤14) ions produced by an electron-beam ion source and extracted at 2.3 kV interacted with a molecular-target gas jet located in the ionization region of a time-of-flight spectrometer. The resulting molecular recoils and fragments were analyzed by time of flight. For a given molecular target, the measured spectra are all similar and do not depend on the incident argon-projectile charge state. The spectra are dominated by the singly charged ion, either N2+ or CO+. The stable or long-lived metastable doubly charged molecular ion CO2+ is the second most prominent feature in Arq+ on the CO spectra. Similarly, N22+, which cannot be distinguished from N+, is also presumed to be present in Arq+ on the N2 spectra. The remaining peaks are associated with the dissociation of the N2Q+ and COQ+ (2≤Q≤6) molecular ions formed in the collision. The peak positions correspond to fragments of a given mass-to-charge ratio and kinetic energy calculated assuming vertical target ionization