  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.
