Electronically excited states and visible region photodissociation spectroscopy of Au(m)(+) . Ar(n) clusters (m=7-9): molecular dimensionality transition?
Photodissociation spectra were determined for Au(m)(+) . Ar(n) (m=7; n=0-3 and m=8,9; n=0,1) in the photon energy range of 2.14-3.02 eV. Experimental data were compared with predictions of dipole allowed transitions using time-dependent density functional theory (TDDFT) as applied to cluster structures from both DFT (B3-LYP functional) and ab initio calculations at the MP2 level. Argon adduct formation does not significantly perturb the bare metal cluster core structure, but it does change the metal cluster spectrum for highly symmetric cluster structures. The photodissociation spectra are consistent with a transition from planar to three-dimensional gold cluster core geometries between m=7 and m=8 for both n=0 and 1. TDDFT predictions for favored isomers describe experimental absorption features to within +/-0.25 eV. We also discuss size-dependent trends in TDDFT transition energies for the lowest energy two- and three-dimensional structures of Au(m)(+)(m=3-9).
Gloess
Alexia N
AN
Institut für Physikalische Chemie, Universität Karlsruhe, Kaiserstrasse 12, Karlsruhe, Germany.
Schneider
Holger
H
Weber
J Mathias
JM
Kappes
Manfred M
MM