Selective single-electron capture into (n, l) subshells in slow collisions of C6+, N6+, O6+ and Ne6+ with He, H2 and Ar

Abstract

By means of VUV photon spectroscopy absolute (n, l)-subshell-selective electron capture cross sections sigma nl have been determined for collisions of C6+, N6+, O6+, Ne6+ with He; C6+, N6+, O6+ with H2 and O6+ with Ar, in the velocity range 0.15-0.5 au. These cross sections depend strongly on the collision velocity, in contrast with total cross sections for electron capture and cross sections for capture into different n shells. One n shell is predominantly populated. The comparison of sigma nl( nu ) for different ions with the same ionic charge suggests that the structure of the ionic core is not very important for the l distribution, as long as the energy levels of the ionic species under consideration are almost hydrogen-like. The comparison of results for O6+-H2, Ar shows that the binding energy of the target is much more important than its internal structure for the resultant shape of sigma nl( nu ).