Double charge transfer spectroscopy for N22+ and CO2+ at vibrational resolution

Doubly charged molecular ions (dications) of N-2 and CO have been studied using a double charge transfer (DCT) spectrometer capable of resolving vibrational levels. The vibrational structures of low-lying singlet states are observed in the translational energy spectra of H- ions produced by double electron capture collisions of Hi projectiles. The observed spectra are well reproduced using the theoretical Franck-Condon (FC) profiles calculated from the best available ab initio potential curves. This suggests that the DCT process obeys the FC principle, i.e., the vertical transition from a neutral molecule to the corresponding dication. (C) 2001 Elsevier Science B.V. All rights reserved.