Effective dielectric permittivity of a random collection of fine metallic particles with an account of multipole interaction

The account of interaction between inclusions in matrix disperse systems (MDS) when considering the propagation of electromagnetic radiation (EMR) in disordered composite systems presents a complicated and still unsolved problem. For the study of the processes of EMR interaction with such systems, the method of effective medium is widely used. It consists of MDS with dielectric permittivity values distributed between the matrix and inclusions are replaced by homogeneous and continuous medium with effective dielectric permittivity ε˜ depending on dielectric permittivities both of the matrix ε˜ ₀ and of inclusions ε, as well as on the inclusion concentration and their statistical distribution in the matrix. This approach gives a result that is in good agreement with experiment, in the case of the wavelength exceeding greatly the mean particle dimensions and the distance between particles. In the case of MDS with a small concentration of spherical inclusions, the Maxwell-Garnet approximation is used