2005 7th Annual Meeting of the Northwest Section
Friday–Saturday, May 13–14, 2005;
Victoria, BC, Canada
Session G1: Condensed Matter II
2:00 PM–4:49 PM,
Saturday, May 14, 2005
MacLaurin
Room: D110
Chair: Geoff Steeves, University of Victoria
Abstract ID: BAPS.2005.NWS.G1.1
Abstract: G1.00001 : Probing the Unique Size-Dependent Electronic and Structural Properties of Nanoclusters
2:00 PM–2:36 PM
Preview Abstract
Abstract
Author:
Lai-Sheng Wang
(Department of Physics, Washington State University and Chemical Science Division, Pacific Northwest National Laboratory)
Materials in the nanometer size scale exhibit properties
different from their bulk counterparts and these properties
depend on particle size and shape. This forms the basis for
nanoscience and nanotechnology. In our laboratory, we use the
bottom-up approach to probe the unique electronic and structural
properties of atomic clusters as a function of size from a few to
few tens of atoms. Atomic clusters are produced using a laser
vaporization cluster source and are studied by photoelectron
spectroscopy in combination with quantum calculations. In this
talk, I will focus on our recent studies on small boron and gold
clusters. One of the most interesting features of elemental boron
and many bimetallic boron compounds is the occurrence
of highly symmetric icosahedral clusters. I will present
experimental and theoretical evidence that small boron clusters
in fact prefer planar structures [1-3], completely different from
bulk boron. We also found that these planar boron clusters
exhibit properties of aromaticity, i.e.,
electron delocaliztion similar to common aromatic organic
molecules. Gold is very different from boron. But small
negatively charged gold clusters have also been shown to assume
planar structures up to 12 atoms. I will discuss joint
photoelectron spectroscopic and theoretical efforts
to confirm the planarity of small gold cluster [4]. The discovery
of a unique 20 atom tetrahedral gold cluster [5] will be
presented, and its novel properties and potentials for catalytic
applications will be discussed. Recent effort to synthesize the
tetrahedral Au$_{20}$ cluster in solution will also be reported [6].
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\textbf{References} \newline
[1] H. J. Zhai, A. N. Alexandrova, K. A. Birch, A. I. Boldyrev,
and L. S. Wang, \textit{Angew. Chem. Int. Ed.} \textbf{42},
6004-6008 (2003).
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[2] H. J. Zhai, B. Kiran, J. Li, and L. S. Wang, \textit{Nature
Materials} \textbf{2}, 827-833 (2003).
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[3] S. K. Ritter, \textit{Boron Flat Out}. \textit{Chem. \& Eng.
News} \textbf{82}, March 1 (2004); pp.28-32.
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[4] H. Häkkinen, B. Yoon, U. Landman, X. Li, H. J. Zhai, and L.
S. Wang, \textit{J. Phys. Chem. A} \textbf{107}, 6168-6175 (2003).
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[5] J. Li, X. Li, H. J. Zhai, and L. S. Wang, \textit{Science}
\textbf{299}, 864-867 (2003).
\newline
[6] H. F. Zhang, M. Stender, R. Zhang, C. M. Wang, J. Li, and L.
S. Wang, \textit{J. Phys. Chem. B} \textbf{108}, 12259-12263 (2004).
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2005.NWS.G1.1