The distribution of excitation resulting from electron capture in stripped-ion-hydrogen-atom collisions

The Monte Carlo classical trajectory method has been used to study the distributions of excitation in projectile ions resulting from electron capture in collisions between fully stripped carbon, oxygen and boron ions and atomic hydrogen at intermediate collision energies (vsub(rel) =1-1.7 au). In this approach, the classical distributions in angular momentum and binding energy obtained for the post-collision hydrogenic projectile ion are converted to effective n and l distributions. It is found that at v = 1 au, the n levels tend to be selectively populated (n = 4 for C5+, n = 5 for 07+ and a combination n = 3 and n = 4 for B4+), but as the collision velocity increases, the n distributions broaden considerably. In general, the most important specific excitations correspond to the highest quantum mechanically allowed values of 1 (4f for C5+, 5g for 07+, 3d and 4f for B5+). Studies of the impact parameter dependence of the C6+ +H excitation at v = 1 show that the angular momentum is strongly correlated to the impact parameter with the dominant excitation shifting from 4 d to 4 f as the impact parameter increases above 2 au. (author)