Semiclassical approach to surface plasmons in spheroidal clusters

The linearized Vlasov equation gives a semiclassical version of the random phase approximation. The solution of this equation is studied for electrons moving in a deformed equilibrium mean field which is approximated by a cavity of a spheroidal shape (both prolate and oblate). Contrary to spherical systems, there is a coupling between excitations of different multipolarity induced by the interaction between constituents. The dipole response presents a typical double-peaked profile with a strong dependence on the deformation.