Two-electron capture into autoionising configurations N4+(1snln'l') with n=2, 3, 4 and n'⩾n, observed by electron spectrometry in collisions of N6+(1s) with He and H2, at 4.2 keV amu-1

Double electron transfer into autoionising states N 4+ (1snln'l'), with n=2, 3, 4 and n'>or=n, has been observed in a collision between a one-electron highly charged N 6+ (1s) ion and a two-electron target (He or H 2 ), by electron spectrometry at 11.6 degrees and 4.2 keV amu -1 . The same configurations are excited in the two collisional systems, but with very different probabilities. Electron capture mainly occurs into 1s2ln'l' in N 6+ -He whereas transfer into 1s3ln'l' is stronger in N 6+ -H 2 .