Evidence for highly energetic fragments following electron capture in O5++H2 collisions at low impact velocities

Angular distributions of recoiling H-2(+) and H+ ions following collisions of slow O5+ and H-2 were measured. The recoil ions originating from single or double electron capture were detected at angles in the range 20degrees-130degrees. At projectile velocities lower than 0.1 au, two groups of peaks are clearly visible. A first structure, centred at similar to9.5 eV, corresponds to a double capture at relatively large impact parameters (b approximate to 5 au). At higher fragment energies, another structure is clearly observed. The latter group of peaks shifts towards lower energies as the detection angle increases. Calculations using classical kinematics equations show that these peaks are due to single or double capture at very small impact parameters (b < I au). Our calculations reproduce the position of the peaks, as well as the relative cross sections as a function of the detection angle.