Linear clusters made by tightly connecting two or more metallic nanoparticles
have new types of surface plasmon resonances as compared to isolated
nanoparticles. These new resonances are related to the size of the junction and
to the number of interconnected particles and have direct interpretation as
eigenmodes of a Boundary Integral Equation (BIE). This formulation allows
effective separation of geometric and shape contribution from electric
properties of the constituents. Results for particles covered by a thin shell
are also provided. In addition, the present analysis sheds a new light on the
interpretation of recent experiments from literature.Comment: 12 pages, 3 figures, to be published in Plasmonics and posted onlin