Development and applications of accurate measurement of X-ray absorption The X-ray extended range technique for high accuracy absolute XAFS by transmission and fluorescence

摘要

Over recent synchrotron experiments and publications we have developed methods for measuring the absorption coefficient in the XAFS (X-ray Absorption Fine Structure) region and far from an edge in neutral atoms, simple compounds and organometallics which can reach accuracies of below 0.02%. This is 50-500 times more accurate than earlier methods, and 50-250 times more accurate than claimed uncertainties in theoretical computations for these systems. The data and methodology is useful for a wide range of applications, including dominant synchrotron and laboratory techniques relating to fine structure, near-edge analysis and standard crystallography. The experiments are sensitive to many theoretical and computational issues, including correlation and convergence of individual electronic and atomic orbitals and wavefunctions.