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Lecture Paul Bagus


17 August 2007 FWN-Building 5114.0004, Nijenborgh 4, 9747 AG, Groningen
Speaker:Prof. Paul Bagus
Affiliation:Department of Chemistry, University of North Texas, Denton, USA
Title:Core-level binding energy shifts in pure and mixed metal nanoparticles
Date:Fri Aug 17, 2007
Location:FWN-Building 5114.0004
Host:Ria Broer
Telephone:+31 50 363 4374


X-Ray photoemission binding energies, BE's, of the core-levels of atoms in metal nano-particles shift as the size of the particles are changed and as the atomic composition of the particles change. It is common to relate these BE shifts to the charge state of the ionized atom; however, this oversimplification neglects other aspects of the particle's chemical interactions that contribute to the BE shifts. It was shown by Richter et al. Phys. Rev. Lett. 93, 026805 (2004), that changes in the distances between atoms in the particle made a major contribution to the BE shifts. Here, the theoretical investigation of the BE dependence on inter-atomic distances is extended to particles of other metals, Ag, Au, Pt, and Ru and to particles with substitutional impurities of Pt in Ru and Ru in Pt. It is shown that the magnitude of the BE shifts due to changes in the inter-atomic distances depends on the atom being ionized and that the BE shifts for Ru are small. Further, it is established that these BE shifts are dominantly initial state shifts and, hence, reflect the chemistry of the particle. The role of nd hybridization and bonding for the chemical origins of the BE shifts is investigated.
Last modified:22 October 2012 2.30 p.m.