Cluster calculations of optical absorption spectra of 2D metal particles arrays: cluster size effects

The optical extinction cross-sections of well-organized two-dimensional 2D.arrays and of one-dimensional 1D.chains of metal nanoparticles are investigated from cluster-like calculations. We mainly focus on the location of the plasmon resonance frequencies. The influence of the cluster size is studied through the shift between these resonance frequencies. The convergence with respect to the number, N, of particles of the cluster depends strongly on the dimensionality of the cluster and only a weak convergence, A1rN1r2, is obtained in the 2D case. A way to avoid the cluster size effect and to get the calculated result for an infinite system is proposed. Finally, a comparison with experimental results for silver particles well organized in a 2D hexagonal lattice is given. q2000 Elsevier Science B.V. All rights reserved