Unraveling the Evolution and Nature of the Plasmons in (Au Core)–(Ag Shell) Nanorods



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Evolution of the sizes and plasmonic properties of (Au core)−(Ag shell) nanorods is studied. Four plasmon bands are observed on the core−shell nanorods and their properties are investigated. The lowest-energy one belongs to the longitudinal dipolar plasmon mode, the second-lowest-energy one belongs to the transverse dipolar plasmon mode, and the two highest-energy ones are ascribed to octupolar plasmon modes.