The study of copper ion (Cu2+) environment in aqueous solution was performed by means of X-ray absorption spectroscopy. X-ray absorption spectra for various concentrations of aqueous solutions of CuCl2 were measured. The testing of near-edge fine structure approach for calculating X-ray absorption Cu K-edge spectra of copper ion (Cu2 +) coordinated complex by finite difference method for solution of Schrödinger equation were held . A model of local environment of copper ion (Cu2 +) in aqueous solutions is proposed.
Keywords: X-ray absorption spectroscopy, 3d-metals ions, aqueous solutions, local environment, finite difference method, coordination complexes
A study of X-ray absorption spectra depending solution of copper (II) and cobalt from the time of preparation of these solutions (immediately prior to the measurement and aged for six months), as well as the dependence of the spectra on the acidity of the solution (different levels of pH 5.7 and 1, which is achieved by addition of hydrochloric acid). Processing of the experimental spectra were in the software package Athena. The study established according to the experimental X-ray absorption spectra of the solution of copper (II) and cobalt chloride on the test conditions.
Keywords: X-ray absorption spectroscopy, soft X-rays, copper chloride, copper (II), cobalt chloride aqueous solution, X-ray absorption spectrometer Rigaku R-XAS, a cell with kapton window
Fe-doped AlN nanorods were studied by means of x-ray absorption spectroscopy above the Fe K- and L2,3- edges. Theoretical simulations of the x-ray absorption spectra show that Fe atoms mainly substitute Al. A minor fraction of Fe interstitials or Fe-Al-N ternary alloy can be identified as well. Bader’s AIM analysis predicts that neutral substitutional FeAl defect is in 2+ charge state, though Al in pure AlN is in 3+ charge state. Fe L2,3 absorption spectra and photoluminescence data indicate the coexistence of Fe2+/Fe3+ in AlN:Fe nanorods so different charge states of substitutional FeAl should co-exist.
Keywords: diversification of management, production diversification, financial and economic purposes of a diversification, technological purposes of ensuring flexibility of production
Alzheimer's disease is an incurable illness. It affects about half a million people in Russia, and due to the general trend towards aging of the population the number of Alzheimer's disease cases will steadily increase. Insoluble deposits of amyloid beta in the brain tissue (amyloid plaques) are the major morphological characteristic of Alzheimer's disease. It has been found that the increased concentration of copper in amyloid plaques results in copper ions bound to the protein. It is the presence of copper in the binding site triggers of the formation of amyloid plaques. Therefore, the study of the binding site in amyloid beta is of great scientific interest. The local atomic structure of the Cu(I) copper ion binding site in the amyloid beta peptide has been studied by means of XANES spectroscopy. Several model structures obtained by molecular mechanics and density functional theory (ADF code) have been tested. Theoretical analysis of X-ray absorption spectra based on the finite difference method implemented in FDMNES code was performed. An appropriate model structure of the Cu(I) copper ion binding site in amyloid beta peptide has been found.
Keywords: amyloid beta, binding site, Alzheimer's disease, the method of finite differences, Cu(I)
Combined method which allows analyzing parameters of the nanoscale atomic and electronic structure of materials relying on three different methods (x-ray absorption spectroscopy (XAFS), x-ray diffraction (XRD) and Raman spectroscopy) was developed. The method was applied for the study of nickel oxide nanoparticles, which serve as an efficient catalyst for the artificial photosynthesis process.
Keywords: solar energy, artificial photosynthesis, NiO, Raman, x-ray diffraction, XAFS
We have carried out the analysis on the scientific and technological literature on methods of calculation and analysis of the x-ray diffraction, x-ray absorption and Raman spectra used to analyse the structure of the materials for hydrogen storage under realistic operating conditions. The simulations were carried out for the series of small palladium nanoclusters with embedded hydrogen. Multiscale computer modelling was used to simulate the dynamics of structure of the materials during charge/discharge phases.
Keywords: hydrogen storage, XANES, x-ray diffraction, Raman scattering, fuel cell