Collision spectroscopy of theHe+-CO,He+-NO, He-CO, and He-NO systems

We present a comprehensive investigation of the ${\mathrm{He}}^{+}$-CO, ${\mathrm{He}}^{+}$-NO, He-CO, and He-NO collisions in the $0.5<\mathrm{}{E}_{\mathrm{lab}}<3\mathrm{}$-keV energy range. The comparison of ionic and neutral systems allows a determination of the excitation mechanisms that are common or specific to each case. In the course of this study new states of the ${\mathrm{CO}}^{+}$ and ${\mathrm{NO}}^{+}$ molecular ions were discovered. The previously proposed excitation mechanisms—(i) direct Demkov-type transitions populating the exothermic charge-exchange channels, (ii) molecular-orbital (MO) promotion giving rise to MO crossings and subsequent electron transitions, and (iii) two-electron transitions leading to direct-excitation and charge-exchange processes in the ionic systems—are also found to apply to the present case, thus confirming their generality.