STATE-SELECTIVE ONE-ELECTRON CAPTURE BY GROUND-STATE N2-2) IONS IN SLOW COLLISIONS WITH HE, NE AND AR USING DOUBLE TRANSLATIONAL ENERGY SPECTROSCOPY((P)

Double translational energy spectroscopy (DTES) has been used to study state-selective one-electron capture by pure ground-state N2+ 2s(2)2p (P-2) ions in collisions with He, Ne and Ar at energies within the ran ge 1.75-8.0 keV. The main collision channels have been identified and their relative importance has been assessed quantitatively. These meas urements avoid the ambiguities inherent in the interpretation of previ ous TES measurements carried out using primary N2+ ion beams containin g unknown fractions of metastable N2+ 2s2p(2)(P-4) ions. In the absenc e 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.