We examine the equations to obtain atomic pair distribution functions (PDFs) from x-ray, neutron and electron powder diffraction data with a view to obtaining reliable and accurate PDFs from the raw data using a largely ad hoc correction process. We find that this should be possible under certain circumstances that hold, to a reasonably good approximation, in many modern experiments. We describ...

The structure of the Au/Si(557) surface is determined from three-dimensional x-ray diffraction measurements, which directly mandate a single Au atom per unit cell. We use a "heavy atom" method in which the Au atom images the rest of the structure. Au is found to substitute for a row of first-layer Si atoms in the middle of the terrace, which then reconstructs by step rebonding and adatoms. The ...

The atomic pair distribution function (PDF) analysis of X-ray powder diffraction data has been used to study the structure of small and ultra-small CdSe nanoparticles. A method is described that uses a wurtzite and zinc-blende mixed phase model to account for stacking faults in CdSe particles. The mixed-phase model successfully describes the structure of nanoparticles larger than 2 nm yielding ...

The title compound, [Ag(C(3)H(3)N(2))](n), has an infinite helical chain structure in which each pyrazolate group bridges two Ag(I) atoms related by a 2(1) axis with an intra-chain Ag⋯Ag separation of 3.3718 (7) Å. Each Ag(I) center is linearly coordinated by two N atoms [N-Ag-N angle = 169.98 (14)°]. The chains are held together by inter-chain Ag⋯Ag inter-actions [3.2547 (6) Å], forming a two-...

Coherent X-ray diffraction imaging is a promising technique for visualizing the structures of non-crystalline particles with dimensions of micrometers to sub-micrometers. Recently, X-ray free-electron laser sources have enabled efficient experiments in the `diffraction before destruction' scheme. Diffraction experiments have been conducted at SPring-8 Angstrom Compact free-electron LAser (SACLA...

Diffraction methods are used to detect atomic order in solids. While uniquely ergodic systems with pure point diffraction have zero entropy, the relation between diffraction and entropy is not as straightforward in general. In particular, there exist families of homometric systems, which are systems sharing the same diffraction, with varying entropy. We summarise the present state of understand...

Multiple-wave Diffraction Anomalous Fine Structure (MDAFS), a new method combining the X-ray multiple-wave diffraction with diffraction anomalous fine structure (DAFS) technique, provides the long-range order structure information by measuring the multiple-wave diffraction profiles in the vicinity of an absorption edge. The real part of dispersion correction and fine structure function can be o...