The testing of technique for modeling the local atomic structure and X-ray absorption spectra for zinc ions in an aqueous solution in the presence of arachidic acid has been adjusted. Models of the local structure of zinc with different coordination geometries are considered: planar, pyramidal, tetrahedral, and octahedral. The cases of increasing distances between the zinc ion and water molecules in the plane and in the axial direction are simulated for octahedral coordination. It has been established that the most probable change in the local structure of the zinc environment in solution in the presence of arachidic acid is the removal of water molecules from zinc ions in the axial position and their further replacement with the formation of a bond with the carboxyl group of arachidic acid.

Keywords: arachidic acid, lipid layer, local atomic structure, X-ray absorption spectroscopy, total external reflection, zinc, biomembrane, finite difference method, monolayer

The local atomic and electronic structure of PANI / Cu nanocomposite was studied by X-ray absorption spectroscopy. It was found that as a result of the formation of a nanocomposite, the polymer chain is transformed by π electronic subsystem and changes local structure of copper. Polyaniline in composite is partially oxidized and protonated.

Keywords: polyaniline, polymer-inorganic composites, X-ray absorption spectroscopy, electronic structure, conductive polymers