Определение параметров локальной атомной структуры методом совместного анализа EXAFS- и EXELFS-данных

Abstract

A method has been developed for studying the local atomic structure of 3d-metal-light element systems based on a joint analysis of the EXAFS and EXELFS data. This method permits to form a mathematical connection for the joint processing of experimental data; it takes into account the theoretical formalism of both X-ray absorption and electron beam scattering for the analysis of compounds consisting of chemical elements, the scattering parameters of which vary greatly. The analysis of the simulated and experimental EXAFS and EXELFS spectra has shown that for a one- and two-component object under study, the problem contains a complete set of initial data, which ensures obtaining the desired functions with minimal errors. When studying objects containing three or more chemical elements, the problem of the lack of information arises, and the parameters of the local environment can only be obtained for those atoms for which the experimental data are analyzed. The obtained experimental results were compared with the model calculations. It is shown that the experimental parameters of the local atomic structure coincide with those obtained by the model calculations, which are within the error limits of the method. The comparison of the found PCFs (pair correlation functions) with the data of the model calculations makes it possible to unambiguously identify peaks that have no physical meaning.