Production of the 2s2p2 2De triply excited state in collisions of quasi-free electrons with He-like B3+, C4+, N5+, O6+, and F7+ ions

We report on a study of the isoelectronic sequence of the 2s2p2 2De triply excited state formed in collisions of He‐like B3+, C4+, N5+, O6+ and F7+ ions with H2 gas targets. The ions were prepared in a mixture of 1s2 1S ground state plus 1s2s 3S metastable state that allowed for the formation of the 2s2p2 2De state via the process of resonant transfer and excitation (RTE). The electron yield from the decay of this state to the 1s2s 3S and 1s2p 3P states was recorded at zero degrees with respect to the beam direction. Absolute singly differential cross section measurements were obtained after determining the 1s2s 3S fraction for each ion beam experimentally. Fairly good agreement between the measured and calculated single differential cross sections was observed.