State-selective electron capture by slow N4+ ions in collisions with helium

Abstract

Translational energy spectroscopy in an apparatus previously developed in this laboratory has been used to study one-electron capture by 4-28 keV N4+ ions in collisions with helium. The main excited N3+ product channels have been clearly identified and the relative cross sections determined. The two main channels are found to involve core rearrangement. While the N3+ 2p2 1 S product channel is dominant, it is shown that other channels involving large energy defects contribute significantly at the higher energies thereby resulting in an essentially energy invariant total one-electron capture cross section: MCLZ calculations, which have also been carried out, satisfactorily predict the main 2p2 1 S product channel but fail to account for the other channels arising from curve crossings at small internuclear separations.