Direct observation of multi-ionization and multi-fragmentation in a high-velocity cluster-atom collision

IPMWe report the direct observation of the multi-ionization of the $H_{21}^+$ hydrogen cluster in a single collision with a helium atom at 60 keV/u. Up to quadruple ionization of the cluster was observed and new multi-fragmentation channel were detected. Moreover, the results show two different fragmentation processes of doubly charged $H-{21}^{2+}$ clusters: emission of an $H_2^+$ dimer, or emission of an $H-3^+$ trimer after rearrangement in the cluster prior to fragmentation