Multipolar excitations in small metallic spheres

A dielectric function E(ω,l) appropriate to a small metallic sphere is obtained within the semiclassical infinite barrier model, where l is the multipole order. An excitation diagram in the l,ω plane based on the structure of this function is proposed. It represents the spherical analog of the excitation structure of an infinite medium in the k,ω plane. 8 refs., 1 fig