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Optical Absorption of Small Palladium-Doped Gold Clusters

V. Kaydashev ; P. Ferrari ; Christopher Heard (Institutionen för fysik, Kemisk fysik (Chalmers)) ; E. Janssens ; R. L. Johnston ; P. Lievens
Particle & Particle Systems Characterization (0934-0866). Vol. 33 (2016), 7, p. 364-372.
[Artikel, refereegranskad vetenskaplig]

The effect of Pd doping on the structure and optical absorption of small cationic gold clusters is investigated by a combined photodissociation spectroscopy and time-dependent density functional theory study of Aun+Arp and PdAun-1+Arp (n = 4,5; p = 0,1). While pure Au clusters are planar, the Pd-doped clusters are 3D. UV-visible absorption is studied in the 2.0-4.7 eV photon energy range, allowing the observation of previously unreported absorption bands for Au-4(+) and Au4+Ar. The oscillator strength of the optical transitions is dramatically reduced upon incorporating a Pd atom in Au-4(+) and Au4+Ar, while this effect is less pronounced for Au5+Ar. Analysis of the electron density transfer shows a different influence of Pd with size. While Pd has a formal negative charge in Au3Pd+, in Au4Pd+ most of the charge is attracted by the highly coordinated central Au atom, leaving Pd positively charged, also affecting the induced structural changes. In addition, orbital analysis of the optical transitions is carried out in order to identify the levels involved in the optical absorption of the pure Au and Pd doped clusters. A reduction of the s density near the Fermi energy, induced by Pd doping, causes a quenching of optical absorption.

Nyckelord: gold clusters, optical absorption, palladium doping



Denna post skapades 2016-09-09.
CPL Pubid: 241593

 

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Institutioner (Chalmers)

Institutionen för fysik, Kemisk fysik (Chalmers)

Ämnesområden

Atom- och molekylfysik och optik

Chalmers infrastruktur