From the analysis of experimental X-ray absorption spectra and the calculation of atomic multiplets it is found that the grinding of powder manganites La0.5Ca0.5MnO3 and Nd0.5Sr0.5MnO3 in a vibration mill results in the formation of nanocrystallites and a partial transformation of trivalent manganese ions into tetravalent. It is shown that in nanostructured manganite La0.5Ca0.5MnO3 the energy gap between the occupied and unoccupied states is absent. It os found that Mn2+ ions arise in Nd0.5Sr0.5MnO3 due to more intense deformation during the grinding.

Ni@C nanocomposites and the carbon shells extracted by etching Ni@C in nitric acid have been characterized by means of soft X-ray absorption and X-ray photoelectron spectroscopies. It was found on the base of Ni 2p X-ray absorption spectra and atomic multiplet calculations that Ni traces in the carbon-shell sample are in the Ni2+ state formed probably by nickel nitrate hexahydrate, Ni(NO3)2·6H2O. Second derivatives of C 1s of X-ray absorption spectra and C 1s X-ray photoelectron spectra were used for characterization of functional groups linked to carbon shells of nanocomposites. The application of second derivatives of C 1s of X-ray absorption spectra allowed to confirm AA stacking of carbon layers for highly oriented pyrolytic graphite. The low-energy features in C 1s XAS spectra of Ni@C and carbon-shell samples are found to be of a different nature. Most likely, the low-energy C 1s XAS feature of the carbon-shell sample is formed due to hydrogenation of carbon atom.