The frequency-dependent electric polarizability of an ion or metallic cluster immersed in a plasma is studied in the framework of Bloch's classical hydrodynamic model. Both bound and free electrons are treated as a classical fluid moving in the potential created by the fixed ion and a uniform...

The frequency-dependent polarizability of an ion or metallic cluster immersed 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...

The dielectric function of an electron-ion plasma is studied in quasistatic approximation by use of linear response theory and the technique of cluster expansion. The coherent part of the electromagnetic field is treated classically. A general expression for the susceptibility kernel is derived...