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MS: Fachverband Massenspektrometrie
MS 6: Clusters and Molecules
MS 6.1: Hauptvortrag
Mittwoch, 13. März 2019, 14:00–14:30, U A-Esch 2
Impact of the Coulomb barrier on the electronic and optical properties of polyanionic silver clusters — Klara Raspe1, Norman Iwe1, Madlen Müller2, Franklin Martinez1, •Josef Tiggesbäumker1,3, Lutz Schweikhard2, and Karl-Heinz MeiwesBroer1,3 — 1Institut für Physik, Universität Rostock, Albert-Einstein-Str. 23, 18059 Rostock — 2Institut für Physik, Universität Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald — 3Department life, Light and Matter, Universität Rostock, Albert-Einstein-Str. 25, 18059 Rostock
Polyanions are ubiquitous in nature, but usually a solvent is necessary to stabilize the complexes. Experiments in a molecular beam offer the possibility to exclude effects of the environment and, thus, give access to the properties of the bare systems. A general property of gas-phase polyanions is the presence of a Coulomb barrier, which allows for metastable electron states above the vacuum level. Therefore, electronic relaxation, i.e., electron tunneling through the barrier, has to be taken into account, in particular, after photoexcitation into weakly bound levels. We produce polyanions in a digital radio-frequency ion trap in order to conduct photoelectron spectroscopy on silver clusters AgNz− (N up to 800, z=1..6). Tuning the laser photon energy and recording the corresponding electron spectra the optical spectra are extracted. The analysis reveals, that electron tunneling has to be taken into account in order to determine size and charge-state selective plasmon energies of silver cluster polyanions. The results on AgNz− will be compared to measurements on singly charged AgN+ and AgN−.