A small metal sphere interacting with an incident electromagnetic wave will produce second-harmonic radiation in a quadrupolar mode. A hydrodynamical model for the electron gas is employed and a Green-function formalism is used to solve for the cross section for producing second-harmonic generation. Numerical results are obtained for aluminum and silver.

• Received 9 December 1985

DOI:https://doi.org/10.1103/PhysRevB.33.3756