Berlin 2001 – wissenschaftliches Programm

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A: Atomphysik

A 4: Clusters I: Metal Clusters (joint session A and MO)

A 4.11: Vortrag

Montag, 2. April 2001, 18:15–18:30, H1012

The Energy Dependence of the Decay Pathways of Small Gold Clusters — •Manuel Vogel¹, Klavs Hansen², Alexander Herlert¹, and Lutz Schweikhard¹ — ¹Inst. f. Physik, Johannes Gutenberg-Universität, D-55099 Mainz, Germany — ²Department of Physics, University of Jyväskylä, FIN-40500 Jyväskylä, Finland

Small odd-size atomic clusters of copper-group elements are known to decay by both evaporation of neutral atoms and neutral dimers. A photodissociation study has been performed which quantitatively determines the dimer-to-monomer branching ratio of gold cluster ions as a function of the excitation energy. The investigation is based on time-resolved observation of the delayed photodissociation of size-selected cluster ions stored in a Penning trap. With increasing excitation energy the dimer-to-monomer branching ratio is found to decrease for all cluster sizes under investigation. This observation seems to contradict the predictions from statistical models of unimolecular dissociation. We are currently investigating what kind of assumptions with regard to the systems’ thermal properties have to be made in order to match the theoretical results with the experimental findings.