Morphology and evolution of size-selected metallic clusters deposited on a metal surface:Ag19+/Pd(100)

Abstract

We study size-selected deposition of Ag 19 ϩ clusters on Pd͑100͒ at total kinetic energies of 20 and 95 eV using thermal energy atom scattering and molecular-dynamics simulations. Contrary to the case of Ag 7 where fragmentation is crucial to explain the data, the deposition leads at low temperature to noncompact structures localized around the impact point. We propose a model in which morphology changes take place between 200 and 300 K resulting in well-separated compact structures. ͓S0163-1829͑98͒06907-0͔

Bimodal Distribution in the Fragmentation Behavior of Small Antimony ClustersSbx+(x=Kaiser1, Bernhardt2, Stegemann3 et al. 1999Phys. Rev. Lett.370210View full textAdd to dashboardCite

“…Implantation has been observed for fullerenes and for silver clusters at high impact energies, too [9,31]. Similar observations as we have just discussed for the Sb 8 1 cluster have been made for all investigated cluster sizes Sb x 1 ͑x 3 12͒. In summary we can separate the interaction of positively charged antimony clusters with HOPG in two distinct energy regimes according to the observed phenomena: (i) low collision energy #150 6 30 eV: unimolecular fragmentation and neutralization; (ii) high collision energy $150 6 30 eV: shattering and implantation.…”

“…To prepare interfaces partially covered with clusters it is very important to understand the processes taking place during cluster surface interactions, which might lead to soft landing, neutralization, diffusion limited aggregation, fragmentation, sputtering, and implantation. All of these processes are known to be important, but detailed investigations on them are very rare [3][4][5][6][7][8][9]. Here we present data for the interaction of size-selected antimony cluster cations with highly oriented pyrolitic graphite (HOPG) over an extended energy range (0-600 eV) employing a new experimental setup, which combines the techniques of mass spectrometry and scanning tunneling microscopy (STM) for the elucidation of the underlying physical processes.…”

“…In particular, we will show that unimolecular fragmentation and neutralization are the prevalent processes at low energy (#150 6 30 eV), whereas shattering and implantation become predominant in the high-energy regime. The fragmentation behavior of the Sb 8 1 cluster ion will be discussed as representative for all investigated cluster sizes Sb x 1 ͑x 3 12͒. The experimental setup consists of a three stage molecular beam apparatus coupled to a surface science setup via a scattering and deposition stage [10].…”

“…After the mass spectrometric investigations the surface is transferred to a modified BEETLE-type STM [13] without breaking vacuum. Figure 1 shows fragment ion yield curves for the collision of Sb 8 1 with HOPG as a function of the mean collision energy. At low kinetic energies Sb 4 1 is the almost exclusive fragment ion.…”

Energy-dependent deposition processes of size-selected Ag nanoclusters on highly-oriented pyrolytic graphite

“…On the other hand, studies focusing on clusters remaining on surfaces after collision are limited in number. [12][13][14][15][16] The latter type of experiment is important not only for complementing the former but for directly observing cluster-surface complexes whose total properties are crucial especially from the technological viewpoint. Carroll et al 16 investigated the deposition processes of Ag cluster anions on a graphite substrate by using a combination of scanning tunneling microscopy and classical molecular-dynamics simulations, and have shown that the fate of the cluster depends on the orientation of the cluster against the surface and the target substrate site.…”