ON THE FISSION OF CHARGED ALKALI-METAL CLUSTERS

A deformed jellium model is used to calculate the fission barrier heig ht of Na-24(2+) --> Na-21(+) + Na-3(+) within the Kohn-Sham density-fu nctional theory (i.e., including shell effects). Although the shape of the barrier obviously depends on the parametrization of the fission p ath, we have found that the saddle point corresponds to a configuratio n in which the emerging fragments are already formed and rather well a part. From this result, we offer a simple way to calculate the barrier height for charged trimer emission from alkali-metal clusters of (alm ost) arbitrarily large size and charge state.