Ground and excited state geometrical and optical properties of Au-n (n=2-13) nanoclusters: A first-principles study

The geometrical and optical properties of small gold nanoclusters Au-n (n = 2-13) in the ground and first excited state were studied by combined artificial bee colony algorithm and first-principles calculations. The global minima for all of the clusters are planar in the ground state, which are also preserved in the first excited state. The electronic transition properties obtained at the first excited state indicated that all of the odd-numbered clusters are weakly emissive with tunable excitation energies. In contrast, only two of the even-numbered clusters, Au-4 and Au-6, are emissive with the respective excitation energies of 1.61 eV and 2.35 eV.