Instrument Function in Powder Diffraction

The instrument function for energy-dispersive and angular- dispersive powder diffraction is presented.

Profile Function of Bragg Reflections in Powder Diffraction

The profile function of the Bragg reflection composed of the contributions of the apparent crystallite size and shape, of the anisotropic strain and of the instrument function is presented.

Structural Parameters of Multilayers as Deduced from X-ray Specular Reflectivity: Effect of Statistical Thickness Fluctuations

Thickness fluctuations in multilayers are shown to induce a strong diffuse term in grazing-incidence X-ray reflectivity (GIXR) patterns. Neglect of this effect causes alteration of average roughness and thickness values, derived by fitting of an ideal superlattice to the actual multilayer.

A Commercial Scanner Applied as a Microdensitometer for Gas Electron-Diffraction Photographic Plates

A commercial Agfa Arcus II scanner is found to be applicable for the photometry of gas electron-diffraction photographic plates.

Cross-Section Structure of Cylindrical and Polymer-Like Micelles from Small-Angle Scattering Data. I. Test of Analysis Methods

The application of the indirect Fourier transformation and the square-root deconvolution procedure for a determination of the cross-section structure of cylindrical and polymer-like micelles is investigated using simulated small-angle scattering data.

Determination of a Mean Orientation from a Cloud of Orientations. Application to Electron Back-Scattering Pattern Measurements

The mean orientation of a cloud of individual orientations measured by EBSP (electron back-scattering patterns) is defined on the basis of quaternion algebra and illustrated on a phase- transformation problem in Ti alloys.

Solving Crystal Structures from Powder Data. I. The Role of the Prior Information in the Two-Stage Method

The two-stage method for crystal structure solution and analysis from powder data is analysed. The basic lines of a new approach are proposed.

Solving Crystal Structures from Powder Data. II. Pseudotranslational Symmetry and Powder-Pattern Decomposition

The pseudotranslational symmetry is used as prior information in the powder-pattern decomposition process.

Correlation Effects in Small-Angle Neutron Scattering from Closely Packed Spheres

A computer simulation of correlation effects in small-angle scattering is presented.

A ⁴He Cryostat for Synchrotron Single-Crystal Diffraction Experiments in the Temperature Range 1.6 to 300 K

A new design is presented for a low-temperature sample environment compatible with the high resolution encountered at synchrotron beamlines. Its performance has been demonstrated in magnetic X-ray scattering experiments.

A New High-Resolution X-ray Powder Diffractometer Working in the 3–470 K Range for Phase-Transition Analyses

The performance of a high-resolution X-ray powder diffractometer working in the 3–470 K range is described. The high level of accuracy in peak position (to within 0.002°) and very good angular sensitivity (~10^-4 °K⁻¹) and an equal resolution in the whole range of temperature allow very accurate determination of the lattice parameters and crystal structure.

Ultrasonic Measurements of the Elastic Constants and their Temperature Dependence for Nearly Perfect Single Crystals of Potassium Tetra­chlorozincate (K₂ZnCl₄)

Ultrasonic measurements of the temperature-dependent elastic constants of potassium tetrachlorozincate are presented. An unusual temperature dependence of the C₁₃ component reflects the onset of a soft mode prior to the onset of a ferroelectric-to- incommensurate phase transition.

Rietveld Refinement using Synchrotron X-ray Powder Diffraction Data Collected in Transmission Geometry using an Imaging-Plate Detector: Application to Standard m-ZrO₂

The Rietveld refinement of powder data of standard m-ZrO₂ collected with a new imaging-plate technique is presented.

Verification of Protein Structures: Side-Chain Planarity

Planarity of side chains in protein structures, compared with small-molecule database results.

Analysis of Trade-Offs Between Spatial Resolution and Detective Area in Crystallographic Detectors for Use with Large-Unit-Cell Crystals

Calculations show that, over a large range of cell size, Bragg resolution and X-ray beam width, a single 92 mm diameter micro- channel-plate (MCP) detector outperforms an array of four 256 × 256 mm multiwire proportional chambers. The advantages of the MCP detector are greatest at large cell size, high Bragg resolution and small beam width.

Teaching Diffraction with the Aid of Computer Simulations

A course on diffraction is presented that uses computer simulations of structures and their Fourier transforms for effective teaching.

Derivation of the rotation matrix in general rectilinear systems by means of vector and matrix formalism

A generalized form of a symmetry operator has been derived by vector and matrix formalism. Typical applications of the formula are also provided.

Design of an inverted spindle axis for frozen crystal screening and storage

A device allowing protein crystals to be prescreened in house for diffraction quality and merging statistics before data collection at a synchrotron-radiation facility is presented.

A procedure compatible with X-PLOR for the calculation of electron-density maps weighted using an R-free-likelihood approach

The program RFLEXPL allows one to obtain cross-validated estimates for phase errors in structure factors calculated from an atomic model. It creates a file of structure factors in X-PLOR format that contains the information necessary to calculate weighted maps.

Obtaining crystals in a crucible furnace

A model of an air cooler in a crucible furnace for simultaneous regulation of different crystallization rates in a series of Tammann test tubes with the purpose of obtaining crystals is presented.

Crystallographers

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Mineral scale formation and inhibition edited by Z. Amjad

Admixtures in crystallization by J. Nývly and J. Ulrich

Electrooptic effects in liquid crystal materials by L. M. Blinov and V. G. Chigrinov