Ion Momentum Imaging Study of the Ion-Molecule Charge Exchange Reaction of Ar + CO.

Three-dimensional ion momentum imaging is developed in a combination of ion velocity map imaging technique and delay-line anode ion detection, and it is applied for the ion-molecule charge exchange reaction between Ar and CO. In a center-of-mass collision energy range of 7.23-15.96 eV, CO products are primarily populated at the ground state XΠ and the single-electron excited states AΠ, BΣ, and CΣ; the multielectron excited states of CO are also found at the higher collision energies. The production efficiency profiles of CO are distinctly different from the photoionization electron spectrum of CO, implying that the charge transfer from Ar would be not fast as expected. The strong electron correlations in the short-lived intermediate (Ar-CO) should be responsible for the CO yields at the multielectron excited states.