Subshell-selective electron capture cross sections in collisions of He2+and C4+with atomic hydrogen

The authors report absolute subshell-selective electron capture cross sections sigma nl for all subshells with n=3, 4 in collisions of C 4+ with atomic hydrogen at impact velocities between 0.1 and 0.5 au. In addition, they report sigma 2p for He 2+ -H collisions; this measurement serves as a test case for the accuracy of the authors' experimental method, which is described briefly. The results for both systems compare well with recent theoretical calculations.