Powder diffraction basis

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...

Pinwheel patterns and powder diffraction

Pinwheel patterns and their higher dimensional generalisations display continuous circular or spherical symmetries in spite of being perfectly ordered. The same symmetries show up in the corresponding diffraction images. Interestingly, they also arise from amorphous systems, and also from regular crystals when investigated by powder diffraction. We present first steps and results towards a gene...

VII. Workshop Powder Diffraction Structure Determination and Refinement from Powder Diffraction Data

New techniques have been integrated into EXPO (Altomare et al., 1999), a package devoted to extracting the integrated intensities from an indexed powder diffraction pattern and to solving crystal structures via Direct Methods. An efficient peak-search algorithm and an improved version of the program TREOR90 (Werner et al., 1985) have been introduced in order to offer new tools for a more powerf...

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...

Two-dimensional X-ray powder diffraction