Strongly localized plasmon oscillations in a cluster of two metallic   nanospheres and their influence on spontaneous emission of an atom
  The plasmon oscillations in a cluster of two metallic nanospheres are studied theoretically. Particular attention is paid to the case of nearly touching spheres. Simple analytical expressions have been found for the spectra of plasmon oscillations of different symmetry in this case. A new type of the plasmon oscillations, which are strongly localized between the spheres, and which totally disappear at separation of the spheres, has been discovered. The found plasmon oscillations have a dramatic effect on optical properties of an atom localized between the spheres. 
V.V.Klimov and D.V. Guzatov