Düsseldorf 2007 – scientific programme
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MO: Fachverband Molekülphysik
MO 14: Molecular Clusters
MO 14.6: Talk
Monday, March 19, 2007, 17:45–18:00, 6D
Photoelectron spectroscopy of molecular diamonds — •Kathrin Klünder1, Christoph Bostedt1, Tobias Richter1, Lasse Landt1, Peter Zimmermann1, Thomas Möller1, Trevor Willey2, Tony van Buuren2, Jeremy Dahl3, SG Liu3, and Robert Carlson3 — 1TU Berlin, Germany — 2LLNL, Livermore CA, USA — 3MolecularDiamond Technologies, Richmond CA, USA
Diamondoids are ideal molecular diamond clusters. They are perfectly size- and isomer-selected, neutral and hydrogen-terminated clusters in the diamond bulk lattice configuration. Diamondoids are a perfect system for investigating the electronic properties of semiconductor nanostructures in the molecular limit.
First x-ray absorption experiments of diamondoids showed no particle size dependence of the lowest unoccupied states which has been confirmed by quantum monte carlo simulations. In contrast to the unoccupied states, however, the calculations predict strong quantum size effects in the occupied states.
We have studied the highest molecular orbitals and core levels of a series of diamondoids by means of photoelectron spectroscopy. The experiments were performed at the beamline UE56/2 of the Bessy synchrotron source with a Scienta hemispherical photoelectron analyser. The valence band photoelectron spectra show a clear energy shift of the highest molecular orbitals to lower binding energies for increasing particle size. The results will be discussed and compared to recent theory.