Eur. Phys. J. D 45, 439-446 (2007)
https://doi.org/10.1140/epjd/e2007-00170-1

Self-assembly of Mo₆S₈ clusters on the Au(111) surface

¹ Physikalische Chemie, TU Dresden, 01062 Dresden, Germany
² Institute of Physics, TU Chemnitz, 09107 Chemnitz, Germany
³ Institute of Ion Beam Physics and Materials Research, P.O. Box 510119, FZ Dresden-Rossendorf, 01314 Dresden, Germany

Corresponding authors: ^a igor.popov@chemie.tu-dresden.de - ^b s.gemming@fzd.de - ^c Gotthard.Seifert@chemie.tu-dresden.de

Received: 30 January 2007
Published online: 23 May 2007

Abstract

The preferred adsorption sites and the propensity for a self-organised growth of the molybdenum sulfide cluster Mo₆S₈ on the Au(111) surface are investigated by density-functional band-structure calculations with pseudopotentials and a plane wave basis set. The quasi-cubic cluster preferentially adsorbs via a face and remains structurally intact. It experiences a strong, mostly non-ionic attraction to the surface at several quasi-isoenergetic adsorption positions. A scan of the potential energy surface exhibits only small barriers between adjacent strong adsorption sites. Hence, the cluster may move in a potential well with degenerate local energy minima at room temperature. The analysis of the electronic structure reveals a negligible electron transfer and S-Au hybridised states, which indicate that the cluster-surface interaction is dominated by S-Au bonds, with minor contributions from the Mo atom in the surface vicinity. All results indicate that Mo₆S₈ clusters on the Au(111) surface can undergo a template-mediated self-assembly to an ordered inorganic monolayer, which is still redox active and may be employed as surface-active agent in the integration of noble metal and ionic or biological components within nano-devices. Therefore, a classical potential model was developed on the basis of the DFT data, which allows to study larger cluster assemblies on the Au(111).