The convergence of the multiple-scattering expansion of XAFS and XANES by explicit path-bypath calculations. The approach is based on the fast scattering matrix formalism of Rehr and Albers, together with an automated path finder and filters that exclude negligible paths. High-order scattering terms are found to be essential, especially at low energies. Several factors including the magnitude of curved wave scattering amplitudes, inelastic losses and multiple-scattering Debye-Waller factors control convergence of the expansion. The convergence is illustrated explicitly for the case of diatomic molecules.

Curved-wave multiple-scattering (MS) theory provides a unified treatment of XAFS, encompassing both EXAFS and XANES, as well as a formal equivalence between exact treatments and the (MS) expansion carried to all orders. Recent developments in the theory of XAFS are reviewed with an emphasis on progress in curved-wave MS calculations and on understanding the nature of MS contributions in EXAFS and XANES. In particular, a unified ab initio MS treatment of XAFS is discussed based on a scattering matrix formalism which has sufficient speed and accuracy to treat high-order MS in extended systems. Neither low-order MS nor full MS theories are fully satisfactory. Instead, sufficiently high-order MS appears to be necessary for the convergence of both EXAFS and XANES calculations. The approach also gives a MS interpretation of the [sigma]* shape-resonances observed in XANES. It is shown that these peaks result from coherent, high-order MS. A generalization of the Natoli rule correlating the resonance locations with bond length is obtained.

These proceedings cover the talks delivered by experts and pioneers on various aspects of this field: theory; principles of the techniques; instrumentation; data analysis; data interpretation and state-of-the-art studies. The volume could serve as a texbook for beginners and future workers in this field as well as a reference book for experienced workers. The emphasis is on the educational aspects of the subject but information on the latest progress is also highlighted.

XAFS for Everyone provides a practical, thorough guide to x-ray absorption fine structure (XAFS) spectroscopy for both novices and seasoned practitioners from a range of disciplines. It’s enhanced with more than 200 figures as well as cartoon characters who offer informative commentary on the different approaches used in XAFS spectroscopy. This second edition now includes chapters on spatial and temporal resolution, alternative measurement modes including resonant inelastic x-ray scattering (RIXS) and high-energy resolution fluorescence detection (HERFD), and an expanded chapter on experimental design. In addition, this edition adds new sections on wavelet transforms, blind source separation, free electron lasers, and theoretical XANES standards, as well as three new case studies. XAFS for Everyone covers sample preparation, data reduction, tips and tricks for data collection, fingerprinting, linear combination analysis, principal component analysis, and modeling using theoretical standards. It describes both near-edge (XANES) and extended (EXAFS) applications in detail. Examples throughout the text are drawn from diverse areas, including materials science, environmental science, structural biology, catalysis, nanoscience, chemistry, art, and archaeology. In addition, eight case studies from the literature demonstrate the use of XAFS principles and analysis in practice. The text includes derivations and sample calculations to foster a deeper comprehension of the results. Whether you are encountering this technique for the first time or looking to hone your craft, this innovative and engaging book gives you insight on implementing XAFS spectroscopy and interpreting XAFS experiments and results. It helps you understand real-world trade-offs and the reasons behind common rules of thumb. Key Points: New cases studies will be added to the end of the book Multiple sections are being refreshed or almost completely re-written to reflect the changes in the field since the first edition. For example: important new synchrotron light sources have come in to operation across the world, including NSLS-II in North America, MAX IV and Solaris in Europe, the Taiwan Photon Source in eastern Asia, and SESAME in the Middle East. New analysis software has been developed, while other software has fallen in to disuse. Discussions of wavelength dispersive detectors will be added throughout the book, as well as wavelet transforms

This book is a comprehensive, theoretical, practical, and thorough guide to XAFS spectroscopy. The book addresses XAFS fundamentals such as experiments, theory and data analysis, advanced XAFS methods such as operando XAFS, time-resolved XAFS, spatially resolved XAFS, total-reflection XAFS, high energy resolution XAFS, and practical applications to a variety of catalysts, nanomaterials and surfaces. This book is accessible to a broad audience in academia and industry, and will be a useful guide for researchers entering the subject and graduate students in a wide variety of disciplines.