Bu. Felderhof et al., FREQUENCY-DEPENDENT EXTINCTION CROSS-SECTION OF A SPHERICAL ION OR METALLIC CLUSTER IMMERSED IN A PLASMA, Physica. A, 217(1-2), 1995, pp. 196-213
The frequency-dependent polarizability of an ion or metallic cluster i
mmersed in a plasma is studied for the model of a uniform sphere with
sharp boundary. The electron gas inside and outside the ion or cluster
is treated in the framework of Bloch's hydrodynamic model. Due to the
coupling to the bulk plasma, the sharp absorption lines of the isolat
ed sphere are modified into an infinite sequence of broadened resonanc
e peaks. The first peak corresponds to the Frohlich mode of a metallic
sphere. It accounts for the major part of the integrated extinction c
ross section. The shape of the giant resonance peak deviates strongly
from a Lorentzian.