Translational energy spectroscopy of29N2+2: one-electron capture in collision with He and Ne atoms

The high-resolution translational energy spectrum of 6 keV 29 N 2+ 2 scattered off He and energy change spectra of one-electron capture by the same ion in collision with He and Ne atomic targets are presented. The latter spectra recorded at different ionising electron energy indicate the presence of two metastable excited states at energies of 1.2 and 1.5 eV above the N 2+ 2 (X 3 Pi u ) ground state. Based on the latest ab initio configuration interaction quantum chemical calculations the two states are assigned to N 2+ 2 (C 1 Delta g , b 1 Pi u ) and (C 3 Sigma + g ) respectively.