Absolute cross sections and decay rates for the triply excited B2+ (2s2p(2) D-2) resonance in electron-metastable-ion collisions

Triply excited states of three-electron ions have been produced by resonant transfer excitation (RTE) in metastable two-electron-ion-beam-H-2 collisions. Measurements of the Auger-electron emission in the direction of the ion beam is used to determine the absolute cross sections for formation of the triply excited states and the branching ratios of the corresponding elastic and inelastic electron scattering channels. The results are compared to existing theoretical calculations of the Auger decay rates. Accurate measurements of the double differential cross sections are made on the bases of the known metastable ion beam fractions and known cross sections for RTE from the ground-state component of the beam. The system investigated is B3+ (1s2s S-3) +H-2 leading to the B2+ (2s2p (2) D-2) resonance that decays to B3+ (1s2s S-3), the elastic scattering channel and to B3+ (1s2s S-1) and B3+ (1s2p P-3), two inelastic scattering channels. Physical Review A