Darmstadt 2008 – scientific programme
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MO: Fachverband Molekülphysik
MO 25: Cluster
MO 25.6: Poster
Thursday, March 13, 2008, 16:30–19:00, Poster C1
Electronic structure and optical properties of ideal diamond clusters - diamondoids — Lasse Landt1, Kathrin Klünder1, •Matthias Staiger1, Jeremy Dahl2, Robert Carlson2, Thomas Möller1, and Christoph Bostedt1 — 1Technische Universität Berlin, Germany — 2MolecularDiamond Technologies, Richmond (CA), USA
Diamondoids can be considered a new form of ideal diamond clusters in the (sub-)nanometer size regime. Because they can be perfectly size and isomer selected fundamental investigations about size and shape effects in neutral clusters known with atomic precision are now becoming possible.
We have investigated highest occupied and lowest unoccupied states as well as optical absorption across the gap for a series of diamondoids from adamantane up to hexamantane. The combination of these three investigations paints a comprehensive picture of their electronic structure. All experiments have been performed in the gas phase reproducing the same idealized boundary conditions of interaction-free and neutral clusters typically assumed in theoretical investigations.
We find that the lowest unoccupied states do not show any particle size. The highest occupied states, however, show strong size but only minor isomeric dependencies. These findings are explained with the localization of the lowest unoccupied states on the surface and the highest occupied states in the core of the cluster. The absorption measurements across the gap in the VUV energy regime reveal strong changes of the spectra with the particle shape and symmetry.