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

Abstract

The Monte Carlo classical trajectory method has been used to study the distribution 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 (v_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. The author finds that at v=1 au, the n levels tend to be selectively populated (n=4 for C⁵⁺, n=5 for O⁷⁺ and a combination n=3 and n=4 for B⁴⁺), but as the collision velocity increases, the n distribution broaden considerably. In general, the most important specific excitations correspond to the highest quantum mechanically allowed values of l(4f for C⁵⁺, 5g for O⁷⁺, 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 4d to 4f as the impact parameter increases above 2 au.