Optical Absorption of Small Palladium-Doped Gold Clusters

Research output: Contribution to journalArticlepeer-review

Authors

  • Vladimir Kaydashev
  • Piero Ferrari
  • Christopher Heard
  • Ewald Janssens
  • Peter Lievens

Colleges, School and Institutes

External organisations

  • KATHOLIEKE UNIVERSITEIT LEUVEN
  • Chalmers Tekniska Hogskola

Abstract

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 Au4 + and Au4 +Ar. The oscillator strength of the optical transitions is dramatically reduced upon incorporating a Pd atom in Au4 + 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.

Details

Original languageEnglish
Pages (from-to)364-372
Number of pages9
JournalParticle & Particle Systems Characterization
Volume33
Issue number7
Early online date21 Apr 2016
Publication statusPublished - Jul 2016

Keywords

  • Gold clusters, Optical absorption, Palladium doping