Plasmons in supported size-selected silver nanoclusters

The plasmonic behavior of size-selected supported silver clusters is studied by surface second harmonic generation spectroscopy for the first time. A blue shift of similar to 0.2 eV in the plasmon resonance is observed with decreasing cluster size from Ag-55 to Ag-9. In addition to the general blue shift, a nonscalable size-dependence is also observed in plasmonic behavior of Ag nanoclusters, which is attributed to varying structural properties of the clusters. The results are in quantitative agreement with a hybrid theoretical model based on Mie theory and the existing DFT calculations.