Doubly excited states populated in collisions of O8+ ions with He and H2 at 1.24 keV amu-1

Coincidence measurements between O6+(3,3), (3,4) (or (4,4)) ions and their emitted x-rays have been performed in double capture collisions between fully stripped O8+ ions and He (or H2) targets at 1.24 keV amu-1. Average ratios of autoionization widths towards different continuum states have been extracted from this measurement and compared with predictions of new Feshbach calculations. A complete set of theoretical partial autoionization widths for the singlet (3,3), (3,4) and (4,4) states of O6+ is also given. In most cases our results exclude a dominant population of high-L states by double capture in contrast with previously reported measurements at higher velocities. (author)