Investigation of triply excited states of Li-like ions in fast ion-atom collisions by zero-degree Auger projectile electron spectroscopy

The production of triply excited states of Li-like systems has recently been extended beyond the lithium atom using two different ion-atom collisional techniques: (a) Triple-electron capture into 2s2p2 and 2p3 states of F6+ formed in fast collisions of bare F9+ ions with Ar and Kr atoms and (b) 180° resonant scattering of quasi-free electrons of H2 from the 1s2s 3S metastable state of He-like B, C, N, O and F ions via the 2s2p2 2D resonance. Autoionization energies, decay branching ratios and production cross sections for these states were measured using zero-degree Auger projectile electron spectroscopy and compared to theoretical calculations using hyperspherical close coupling (HSCC) and R-matrix methods.