Auto transfer to Rydberg states during ion-atom collisions

Abstract

Electron capture by slow multiply charged ions colliding on rare‐gas targets is known to populate highly excited states of the projectile. On the basis of experimental measurement of energy and angle differential cross‐sections we have shown that capture to a resonant doubly excited state may lead to Autoionizing Double Capture (ADC) as well as to True Double Capture (TDC). In this model TDC appears as a two step post‐collisional process, the state populated by the collision decays to (or delutes into) a dense adjacent Rydberg series, followed by radiative deexcitation of the inner electron of the (3,n) Rydberg states. We report here new experimental observations in electron spectra measured in N7++He. Auto transfer to Rydber states has also important consequences on the determination of the lifetime of the autoionizing states, some discrepancies between theoretical width values for low N5+(4,4) resonant states will be discussed and partially resolved.