Coupled-multipole formulation for the treatment of electromagnetic scattering by a small dielectric particle of arbitrary shape

A generalization of the coupled-dipole method introduced by Purcell Pennypacker [Astrophys. J.186, 705 (1973)], a low-frequency method used to describe electromagnetic scattering by dielectric objects of arbitrary shape, is proposed. At each site of the cubic lattice, instead of a dipole moment there are an electric dipole, a magnetic dipole, and an electric quadrupole, leading to an improved description of the scattered fields.