Shkoda N. Scattering and absorption of electromagnetic radiation by small multi-layered particles and matrix-dispersed systems on their base

It is found exact solutions for EMR scattering by a multi-layered sphere and by a sphere with anisotropy shell. The sphere's polarizabilities as well as their scattering and absorption cross-sections are calculated. From the obtained solutions, it is calculated the extinction coefficient for a system of colloidal silver particles ( 5…20 nm), and the resonance absorption bands are shown to arise in the optical spectra of the matrix dispersed systems. The bands at 350…430 nm (absentee in case of bulk silver) correspond to surface modes of small silver particles, and calculated bandwidth and absorption peak height are in good agreement with the experimental data obtained at the Institute of Surface Chemistry. It is elaborated theoretical methods for defining the effective dielectric function of the matrix-dispersed systems with multi-layered spherical inclusions with taking into account both the size distribution of the inclusions and direct multipole interaction between them. The systems' absorption spectra are calculated. It is solved the inverse electrodynamical problem of dielectric spectroscopy for the matrix-dispersed systems with multi-layered ellipsoidal inclusions. A method for defining electro-physical parameters of the inclusions from experimental frequency dependence of the effective dielectric function of the systems and from adequate systems' electrodynamical model is proposed. By using the proposed numerical-analytical method with taking into account experimental dependencies, the electro-physical parameters of the E. Coli bacteria cells are calculated. Obtained parameters values agree well with their known values defined by using other methods.