Dielectric Function of a Spherical Metallic Nanoparticle

The interaction of electromagnetic waves with a spherical metallic nanoparticle is studied in this work. Within the model of an infinite spherical potential well, taking into account the size dependence of the Fermi energy, a formula for the dielectric tensor is obtained and its diagonal components are calculated. The calculation results demonstrate a strong size and frequency dependencies of the real and imaginary parts of the dielectric function. Calculations were performed for Ag, Cu, and Al particles.