Full-potential XANES analysis for 3D local structure investigation of isocyanide Ni complex

A novel technique of 3D local structure refinement using full-potential X-ray Absorption Near Edge Structure (XANES) analysis is proposed and demonstrated in application to planar Ni complex (tetrakis-tert-phentyl isocyanide Ni(II) perchlorate). It can be applied to determine local structure also in other cases (like nanoclusters or nanotubes) where the muffin-tin (MT) approximation for the potential fails. The method is based on multidimensional interpolation of the XANES spectra as a function of structural parameters and ab initio full-potential calculations of XANES using finite difference method. The possibility to extract information on bond angles in addition to those accessible to standard EXAFS is demonstrated and it opens new perspectives of quantitative XANES analysis as a 3D local structure probe having nanoscale resolution.