Symmetric charge-exchange reactions of N 2 + -ions investigated by laser-induced fluorescence

The symmetric charge-exchange reaction of fast N ₂ ⁺ ions (U _ion=800 eV) has been investigated by the method of laser-induced fluorescence. The distinction between the primary N ₂ ⁺ ion beam and the N ₂ ⁺ ions formed by charge-exchange was possible because of the different velocities of the two species which resulted in two spectral distributions separated by the Doppler-shift. Simulation techniques have been used in order to obtain rotation-vibration distributions for both the inelastically scattered fast ions and the charge-exchange products. The rotation distributions could be described by a temperature of 1,000 K for the inelastic and 300 K for the charge-exchange process. The latter process exhibits, however, a significant vibrational excitation which is attributed to the existence of a stable intermediate complex of N ₄ ⁺ . The preferred geometry for the intermediate collision complex is assumed to be non-planar.