Optical properties of a silver-island film are interpreted by taking account of retarded dipole-dipole interactions between island particles instead of the static-field interaction. The discrepancies between the values of the structural parameters evaluated from electron micrographs and those evaluated optically with the assumption of the static-field dipole-dipole interaction can be thus interpreted. The retarded dipole-dipole interactions as well as the size effect also broaden the width of the plasma-resonance absorption peaks.
Tomuo Yamaguchi, Sadafumi Yoshida, and Akira Kinbara, "Effect of retarded dipole-dipole interactions between island particles on the optical plasma-resonance absorption of a silver-island film," J. Opt. Soc. Am. 64, 1563-1568 (1974)