New approaches to stored cluster ions

Ion traps are wall-less containers which allow theextended storage of selected species. During the storage variousinteraction steps may be repeatedly applied. To this end nofurther hardware has to be added - in contrast to beamexperiments. In this progress report two examples of recentdevelopments are presented: the experiments have been performedwith metal clusters stored in a Penning (ion cyclotronresonance) trap. A new experimental scheme has been developedwhich allows precision measurements of the dissociation energiesof polyatomic species. It has been triggered by investigationson the delayed photodissociation of stored metal clusters.However, the technique is also readily available for applicationto a broad variety of different species and it is not evenrestricted to trapping experiments. The second development ismore closely connected with ion storage in Penning traps: byapplication of an electron bath singly charged anionicclusters can be converted into multiply charged species.Subsequently, they are charge selected and investigated withrespect to their reaction upon excitation. In particular,preliminary results indicate that dianionic metal clusters emittwo electrons upon photoexcitation whereas the singly chargedspecies show dissociation.