X-ray resonant powder diffraction

X-Ray Powder Diffraction Metrics

To compare sample data from x-ray diffraction a suitable metric is developed to evaluate the similarity (or dissimilarity) between samples and to compare it to a references. The methodology focuses on the d-lines and uses the intensity measurements indirectly in the algorithm. The resulting d-line distribution and summary statistics of the differences is used to establish whether a true differe...

Two-dimensional X-ray powder diffraction

X-ray powder diffraction on proteins

Macromolecular structures are traditionally determined by means of single crystal X ray diffraction from protein crystals of micrometer dimensions. Nevertheless, the growth of good quality single crystals can be very difficult or even impossible, especially in cases of large proteins, membrane proteins or protein complexes. Modern developments of X-ray powder diffraction have allowed the struct...

Resonant soft X-ray diffraction - in extremis.

The use of softer-energy X-rays produced by synchrotron radiation for diffraction is an area of current interest. In this paper, experiments exploiting resonant scattering at the L absorption edges of 3d transition metal elements are reported. Such energies, typically 500-1000 eV, are at the extreme limit of soft X-ray diffraction where absorption effects are so severe that the sample and diffr...

Resonant X-ray Diffraction: basic theoretical principles

We present the main steps governing the theory of resonant x-ray diffraction (RXD). We focus on the derivation of the anomalous scattering amplitude from perturbation theory and starting from the low-energy expansion of the Dirac Hamiltonian. We give the main ingredients of the multipolar expansion in term of electric and magnetic transitions. We also show the expansion in terms of scattering t...