https://doi.org/10.1140/epjd/e2012-30486-4
Regular Article
Modeling thiolate-protected gold clusters with density-functional tight-binding*
1 NanoScience Center, Department of
Physics, University of Jyväskylä, 40014
Jyväskylä,
Finland
2 NanoScience Center, Department of
Chemistry, University of Jyväskylä, 40014
Jyväskylä,
Finland
a e-mail: ville.p.makinen@jyu.fi
Received:
2
August
2012
Received in final form:
28
November
2012
Published online:
6
March
2013
Thiolate-protected gold clusters are complex systems, in which both the surface-covalent Au-S bond and electronic structure of the gold core play an important role for the stability. In this study, a charge-self-consistent density-functional tight-binding parametrization for these systems is validated by studying Au25(SMe)18-, Au102(SMe)44 and Au144(SMe)60 clusters, where recent X-ray structure determinations and density-functional calculations have revealed the detailed atomic structures and electronic properties. We show that the cluster geometries obtained from the tight-binding structure relaxation preserve the Divide and Protect structure motif [H. Häkkinen, M. Walter, H. Grönbeck, J. Phys. Chem. B 110, 9927 (2006)], where the gold core is protected by a number of oligomeric Aux(SR)y units. Furthermore, the electron shell structure in the metal core, composed of Au(6s) electrons, is reproduced. We conclude that the density-functional tight-binding method describes these systems well and offers a possibility to explore their dynamical phenomena.
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2013