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Extended Hückel tight-binding calculations of electronic resonances in linear chains of gold atoms and clusters

Abstract:

Electronic excitations in linear chains and icosahedra clusters of gold atoms have been studied using an approximate version of time-dependent density functional theory based on the extended Hückel tight-binding method. The formation and development of two longitudinal collective resonances in the absorption spectra were studied as a function of the chain length. We show that in the case of a gold cluster dimer, the classical description breaks down at intercluster distances below 0.5 nm due to the neglect of important quantum effects. In addition, a blue shifting of the collective resonances at these distances is observed. Analysis of these results yields a general picture of electronic resonances in one-dimensional atomic structures. © 2010 American Chemical Society.