  The random-phase-approximation semiclassical scheme for description of
plasmon excitations in large metallic nanospheres, with radius range 10-60 nm,
is formulated in an all-analytical version. The spectrum of plasmons is
determined including both surface and volume type excitations and their mutual
connections. The various channels for damping of surface plasmons are evaluated
and the relevant resonance shifts are compared with the experimental data for
metallic nanoparticles of different size located in dielectric medium or on the
semiconductor substrate. The strong enhancement of energy transfer from the
surface plasmon oscillations to the substrate semiconductor is explained in the
regime of a near-field coupling in agreement with recent experimental
observations for metallically nanomodified photo-diode systems.
