Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 9: Nanoparticles, Nanocrystals and Composites II
CPP 9.3: Vortrag
Montag, 7. März 2016, 15:30–15:45, H41
When do clusters start to behave like a solids: A density-functional theory study of noble gas clusters — •Lydia Nemec2, Benjamin Johnson1, Oliver T. Hofmann3, Alexander M. Bradshaw5, and Patrick Rinke4 — 1Fritz-Haber-Institut der MPG, Berlin — 2Technische Universität München — 3Technische Universität Graz, Austria — 4Aalto University, Helsinki, Finland — 5MPG für Plasmaphysik (IPP), Germany
Weakly bonded argon clusters are a popular model system for studying the transition from molecular to bulk behaviour. Angle-resolved photoemission spectra exhibit bulk-like energy dispersion for clusters as small as 200 atoms [1]. To investigate this observation, we performed a density functional theory (DFT) study of Ar and Kr clusters using the all-electron, numeric, atom-centered basis function code FHI-aims. We use semilocal density functionals including van der Waals dispersion terms in the Tkatchenko-Scheffler approach (PBE+vdW). We developed a method to translate cluster states to a k-resolved energy dispersion based on a Fourier transformation of the eigenstates. For low-energy structures taken from the structure database [2], we show that already clusters in the 200 atom size range exhibit a bulk-like atomic structure. We then demonstrate the emergence of a band-like energy dispersion with increasing cluster size. Finally, we discuss the influence of spin-orbit splitting by contrasting Ar with Kr.
[1] Förstel, et. al, J. El. Spec. Rel. Ph. 184, 107-112 (2011) [2] Y. Xiang,et. al, J. Phys. Chem. A, 108, 3586-3592 (2004)