Selective electron capture into He II (n, l) subshells in collisions of He²⁺with atomic and molecular hydrogen

Absolute cross sections were measured for He II Lyman alpha , beta , gamma and Balmer beta emission resulting from collisions of 1.25-10 keV amu -1 He 2+ ions with atomic and molecular hydrogen. Details of the experimental method and the evaluation of the cross section data are presented. From the experimental data cross sections for electron capture into specific (n, l) subshells of He II (2p, 3p, 3s+3d and 4p) were deduced. The cross section for electron capture into the metastable 2s state of He II for atomic hydrogen as target was evaluated using the total capture data of Shah and Gilbody (1974-8) and Nutt et al. (1978). Results of the present measurement are in very good agreement with recent calculations.