We propose a new formalism for computing the optical properties of small clusters of particles. It is a generalization of the coupled dipole–dipole particle-interaction model and allows one in principle to take into account all multipolar interactions in the long-wavelength limit. The method is illustrated by computations of the optical properties of N=6 particle clusters for different multipolar approximations. We examine the effect of separation between particles and compare the optical spectra with the discrete-dipole approximation and the generalized Mie theory.
© 2002 Optical Society of America
Vitaly N. Pustovit, Juan A. Sotelo, and Gunnar A. Niklasson, "Coupled multipolar interactions in small-particle metallic clusters," J. Opt. Soc. Am. A 19, 513-518 (2002)