State-selective one-electron capture by ground-state N²⁺(²P) ions in slow collisions with He, Ne and Ar using double translational energy spectroscopy

Double translational energy spectroscopy (DTES) has been used to study state-selective one-electron capture by pure ground-state N²⁺ 2s²2p(²P) ions in collisions with He, Ne and Ar at energies within the range 1.75-8.0 keV. The main collision channels have been identified and their relative importance has been assessed quantitatively. These measurements avoid the ambiguities inherent in the interpretation of previous TES measurements carried out using primary N²⁺ ion beams containing unknown fractions of metastable N²⁺ 2s2p²(⁴P) ions. In the absence of any detailed theoretical studies, we have calculated Landau-Zener reaction windows for these processes and shown that they accommodate the observed collision channels with limited success.