Eur. Phys. J. D 16, 73-76 (2001)
https://doi.org/10.1007/s100530170063

Decay pathways of small gold clusters^*

The competition between monomer and dimer evaporation

¹ Institut für Physik, Johannes-Gutenberg-Universität Mainz, D-55099 Mainz, Germany
² Institute for Physics, University of Jyväskylä, FIN-40351 Jyväskylä, Finland
³ Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, D-17487 Greifswald, Germany

Corresponding author: ^a manuel.vogel@uni-mainz.de

Received: 2 November 2000
Published online: 15 September 2001

Abstract

The decay pathway competition between monomer and dimer evaporation of photoexcited cluster ions , n= 2-27, has been investigated by photodissociation of size-selected gold clusters stored in a Penning trap. For n> 6 the two decay pathways are distinguished by their experimental signature in time-resolved measurements of the dissociation. For the smaller clusters, simple fragment spectra were used. As in the case of the other copper-group elements, even-numbered gold cluster ions decay exclusively by monomer evaporation, irrespective of their size. For small odd-size gold clusters, dimer evaporation is a competitive alternative, and the smaller the odd-sized clusters, the more likely they decay by dimer evaporation. In this respect, shows an anomalous behavior, as it is less likely to evaporate dimers than its two odd-numbered neighbors, and . This nonamer anomaly is typical for copper-group cluster ions (M = Cu, Ag, Au) and a similar behavior is found in the anionic heptamers . It is discussed in terms of the well-known electronic shell closing at n_e=8 atomic valence electrons.