Possible method to determine the two-dimensional to three-dimensional crossover of gold clusters by examining their vibrational modes

The structural and vibrational properties of Au-N (N <= 16) have been studied by the relativistic all-electron density-functional calculations, in which a particular attention is paid to characterize the two-dimensional (2D) to three-dimensional (3D) crossover by their vibrational modes. There exist distinctly different vibrational spectra for the 2D and 3D Au-N, which could be used as a fingerprint signal to identify their structures. More interestingly, it is found that each isomer of Au-N has its characteristic radial breathing mode, whose frequency shows a remarkable jump at the 2D-3D transition point, thus offering a realizable and powerful experimental tool to determine the 2D-3D crossover size of Au-N. (c) 2006 American Institute of Physics.