Recent gold cluster studies in a Penning trap

A progress report is given on the investigation of metal clusters with an ion cyclotron resonance (Penning) trap. The examples are taken from the recent studies on gold clusters. In particular, the monomer and dimer evaporation is monitored as a function of cluster size. For the particular case of Au-7(+) this study is expanded to include the energy dependence of the branching ratio. In connection with the sequential decay of Au-8(+) the information can be used for a model-free determination of the dissociation energy of Au-8(+). A second line of studies concerns the production, properties and storage behavior of polyanionic gold clusters. Such species have recently been produced by electron attachment to monoanionic gold clusters stored in the Penning trap. While collisional excitation may lead to ion loss due to changes of the ion motion upon electron emission, the competition between electron detachment and neutral atom evaporation can be studied by laser excitation. Small clusters tend to emit electrons, while larger ones evaporate atomic monomers. (C) 2002 Elsevier Science B.V. All rights reserved.