STABILIZED DOUBLE-ELECTRON CAPTURE IN KRQ-KR COLLISIONS( (Q = 17,18))

We have determined the distribution of n states initially populated in a double- or multielectron-capture collision of Kr(q+) (q = 17,18) wi th Kr at low energy (almost-equal-to 5 keV/u). Radiative decay curves of Rydberg transitions of the projectile ions were obtained by transla ting the target gas jet along the projectile beam. As a result for Kr1 8+ projectiles, we found that an initial population of Kr16+ equally d istributed from n = 14 to 19 allows the observed Kr XVII 13-14 radiati ve decay curve to be reproduced relatively well. Furthermore, coincide nce time-of-flight spectroscopy of photons emitted by recoil ions of g iven charge states was used to measure the radiative decay of recoil-i on transitions. From the Kr VII 7i-8k decay curve we deduced an initia l population distribution of the Kr6+ recoil ion centered around n=20. These results lead to a better understanding of the mechanisms of dou ble-electron capture responsible for populating Rydberg states, especi ally those in asymmetric configurations.