We have developed a formalism which allows one to calculate the transmission, reflection and ansorbance of electromagnetic waves by structures having two-dimensional periodicity parallel to a given surface. The structures considered are single layers or multilayers of non-overlaping spheres, embedded in a host material of different dielectric function. A special case of multilayer is a stack of identical layers whose properties, when the thickness of the slab exceeds a certain limit, are identical with those of the corresponding infinite crystal. We present numerical results for specific examples of single layers and multilayers, and point out some interesting physics which came out of our calculations.

We present a formalism for the calculation of the scattering of electromagnetic waves by a substitutionally disordered two-dimensional array of spherical particles. The formalism, which constitutes an extension of the coherent-potential approximation scheme to electromagnetic waves is valid for any frequency of the incident wave and for any size and/or concentration of the particles. We demonstrate the applicability of our formalism by applying it to the evaluation of the absorbance of disordered arrays of plasma spheres.

The formation of localized moments of impurities in simple-metal hosts is investigated in the case of an Mn solute atom in jellia with continuously varying density. The mean-field critical behaviour of the transition from a spin-polarized to a non-spin-polarized state of the impurity, which is deduced from self-consistent local-spin-density (LSD) functional calculations, is analysed assuming a Landau-type expansion of the energy. This analysis is illustrated and supported by constrained LSD functional calculations.

The spin-orbit scattering (SOS) cross section σso of the 5(s, p) impurities is investigated in two different metal hosts. In the simple Mg host we observe a maximum at half filled p shell. This is the first experimental observation of an impurity p resonance and confirms theoretical predictions. For the transition metal host Cu the maximum in σso is shifted towards Te, the impurity with four p electrons. This is due to the hybridization of the Cu d states with the Te p level. The comparison between experimental and theoretical SOS cross sections represents a compact test of the quality of modern self-consistent electronic structure calculations.

We present local density functional calculations for magnetic impurities and magnetic monolayers in non-magnetic metals. The calculations employ a multiple scattering (KKR) Green's function method for impurities in the bulk and for ideal surfaces and interfaces. In particular we discuss the moment formation of 3d and4d impurities in alkali and noble metals. Special emphasis is put on an accurate calculation of the host polarization around 3d impurities in Cu and Pd. While the calculated impurity hyperfine fields in Cu contain rather large errors due to the local density approximation, the induced fields of the Cu atoms agree very well with experiments. We also present similar calculations for magnetic monolayers and the corresponding induced host polarization in Cu and Pd.

We present a systematic study of local spin moments of impurities in alkali-metal hosts, by means of ab initio, local-spin-density electronic structure calculations. Our results predict for the first time that besides the well-known cases of 3d and 4d impurities also 5d and some sp impurities are magnetic in the alkali metals both on substitutional and interstitial positions.