State-of-the-Art Analysis of Whole X-ray Absorption Spectra.

Fitting an entire X-ray spectrum rather than its components, EXAFS and XANES, has been an aim of the practitioners of these techniques. Recent developments have made the calculations of both the scattering and atomic components practicable. We present the analysis of four representative model compounds using the EXCURVE package, which was modified to undertake this. The details of these modifications are also given. A comparison of matrix-inversion and finite-path-sum methods is made which shows that the latter method is more promising for fitting the edge region. A number of enhancements are required before this approach can be used for accurate structure determination. These include improvement in atomic contribution, better potentials/phase shifts, and the ability to calculate and refine multiple-scattering terms to at least fifth order.