Observability of resonance optical structure in fractal metallic clusters

We investigate optical properties of the deterministic network model for fr actal metallic clusters at the percolation threshold. As input data we used the experimental bulk dielectric function of gold, aluminum, and nickel. S harp absorption resonances in the optical spectra are observed only for gol d. They are pronounced only for clusters consisting of particles with sizes larger than the mean free path of the conduction electrons. In smaller par ticles the peaks are heavily damped due to scattering of electrons by the p article surfaces. (C) 2001 American Institute of Physics.