Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 20: Nanostructures at Surfaces II
O 20.9: Vortrag
Montag, 31. März 2014, 18:00–18:15, WIL B321
Do you believe in thermodynamics? Towards a predictive modeling of adsorbed clusters. — •Chiara Panosetti, Dennis Palagin, and Karsten Reuter — Technische Universität München, Germany
Materials applications generally require the stabilization of engineered atomic clusters at solid surfaces. For metal-doped M@Sin cages this can be achieved either via controlled deposition of preformed clusters or direct silicide formation at Si surfaces. Particularly for the latter, technologically appealing approach quantitative theory could effectively aid experimental design by predicting deposition conditions at which desired cluster structures form spontaneously at the surface. We propose to approach this problem by suitably combining configurational sampling within an ab initio thermodynamics framework. Hereby, the stability of globally optimized geometries of different stoichiometry can be compared through evaluation of thermodynamic functions. Our results demonstrate the possibility of a qualitative prediction of experimental mass-spectra abundances of isolated M@Sin clusters, suggesting thermodynamics to primarily rule cluster formation in the cluster source. The possibility of extending this equilibrium picture towards cluster formation at extended surfaces will be critically evaluated.