Local structure parameters through the fitting of XANES spectra using a multidimensional interpolation: application to the Pd K-edge of Pd-diethynylbiphenyl polymer

Anew method of advanced quantitative analysis of x-ray absorption near edge structure (XANES) is described. The method is based on the fitting ofexperimental XANES data using multidimensional interpolation of the spectra as a function of the structural parameters and full multiple scattering calculations. Such an approach has several advantages in comparison with schemes that existed before, in particular a very small number of abinitio calculations, significant reduction of required computational time, and the possibility to see immediately the spectrum that corresponds to any set of structural parameters. A first application of the method to determine the parameters of the local geometry of a real system, namely Pd-diethynylbiphenyl, is reported. The procedure of polynomial construction is described in detail for this complex of palladium. The best-fit three-dimensional geometry obtained has the following bond distances: Pd-P 2.36±0.02 Å, Pd- C2.06±0.02 Å and C-C 1.1±0.03 Å, in agreement withresults of previous EXAFS studies.