Energy transfer in collisions of metal clusters with multiply charged ions

Collisions between low-energy multiply charged ions and neutral metal clusters are an efficient method to investigate charge instabilities in finite systems. We study here the appearance size n_app(q) of multiply charged sodium clusters Na_n^q+ with q<~10, i.e., the smallest size of observation for q-fold charged clusters and its dependence on the collision parameters. The experimental results are compared with the energy transferred to the cluster during the collision, calculated with the semiclassical Vlasov equation within the jellium approximation. Experimental and theoretical data show similar trends with the collision parameters and evidence the importance of dynamical effects. These results guide further investigations for studying low excited multiply charged finite systems.