Nature of the 1385.6 and 1438 eV Positive Glitches in the Transmission Function of the YB₆₆ Soft-X-ray Monochromator

It has been found that the two positive glitches observed at 1385.6 and 1438 eV in the transmission function of the YB₆₆ double-crystal monochromator are caused by the anomalous increases of the reflective intensity of the 006 reflection at the yttrium L_III and L_II absorption edges. The intensities of these two glitches are reduced to minimal values by the installation of an SiC cut-off mirror downstream from the YB₆₆ monochromator.

Solving Crystal Structures from Powder Data. III. The Use of the Probability Distributions for Estimating the |F|'s

A probabilistic method is integrated with the Le Bail algorithm to decompose a powder diffraction pattern: it provides more accurate estimates of the structure-factor amplitudes.

Higher-Order Laue Zone (HOLZ) Line Patterns and their Applications in Determining Microstructures in Barium-Titanate-Based Ceramics

In this paper, higher-order Laue Zone (HOLZ) lines in BaTiO₃ ceramics are obtained and a tiny difference of the lattice parameters between the pure and Ba(Ti,Sn)O₃ ceramics has been observed in nanometre-sized areas.

Probabilities of Random Disorientation Axes in Cubic Polycrystals

The theoretical function describing the probability density of disorientation axes is obtained for cubic polycrystals. An analytical expression for this density function is determined in spherical coordinates to facilitate graphical representation.

Qu­antitative δ' Phase Analysis in Al–Li Alloys using the Rietveld Method

The application of the Rietveld method to different X-ray powder diffraction spectra allows the determination of the mass fraction evolution and the mean size evolution with aging time at 453 K of the δ' precipitates in an Al–Li alloy.

Diffraction Behaviour of Three-Component Fibonacci Ta/Al Multilayer Films

The microstructure of three-component Fibonacci Ta/Al multilayer films is studied by transmission electron microscopy and electron and X-ray diffraction.

Packing Disordered Molecular Crystals and their Molecular Alloys

The packing coefficient in orientational disordered phases for a set of series of compounds derived from neopentane and their molecular alloys is reported in order to analyze the molecular interactions.

Ab Initio Structure Determination of Li₂MnO₃ from X-ray Powder Diffraction Data

The results of the structural determination of Li₂MnO₃ from X-ray powder diffraction data and refinement by the Rietveld technique are presented.

Evaluation of the `Seed-Skewness' Method of Peak Integration

A numerical method for evaluation of the performance of a new peak-integration procedure is presented.

Comparison of the σ(I)/I and Least-Squares Methods for Integration of Bragg Reflections

Various peak integration procedures are compared with an idealized least-squares procedure, and it is shown that, in practical conditions, an analytic σ(I)/I procedure comes very close to the ideal.

The Origin and Minimization of the Critical-Angle Reflection from a Thin-Film Multilayer Monochromator

A neutron beam, reflected by a thin-film multilayer monochromator, will also contain the long-wavelength component of the incident spectrum in addition to the desired band of wavelengths. A number of approaches have been suggested to minimize this contamination.

X-ray Diffraction-Line Broadening Analysis: Paracrystalline Method

Line-profile simulation and matching on the basis of a paracrystalline one-dimensional Hosemann's model provides a promising approach to the analysis of X-ray line broadening and is presented here.

Accuracy of Structural Information Obtained at the European Synchrotron Radiation Facility from Very Rapid Laue Data Collection on Macromolecules

An accurate structural model of native cutinase was derived from Laue data recorded in 8.5 ns at the European Synchrotron Radiation Facility, demonstrating the potential of very rapid Laue data collection for time-resolved studies.

Lithium Fluoride Transmission Phase-Retarder for X-rays

The polarization state of the transmitted beam in Bragg-case X-ray diffraction has been determined.

DISCUS: a program for diffuse scattering and defect-structure simulation

The program DISCUS is a versatile tool for the analysis of diffuse scattering and for defect-structure simulations.

LOCSCL: a program to statistically optimize local scaling of single-isomorphous-replacement and single-wavelength-anomalous-scattering data

Features of a new program for single-isomorphous-replacement and single-wavelength-anomalous-scattering local scaling are described.

SPACER: a program to display space-group information for a conventional and nonconventional coordinate system

A PC computer program developed to display space-group information is described.

A sturdy box design for sitting-drop crystallization

A perspex box for crystal growth by vapour diffusion has been designed.

A multiple-crystal data-collection method in time-of-flight neutron Laue diffraction

The structure of an organic material, acetylcholine bromide, is refined from neutron diffraction data deliberately collected from a multiple-crystal sample. The method developed has clear promise in several areas including allowing more rapid data collections, enabling the use of smaller crystals and studying single-crystal samples in more complex sample environments.

Successful flash-cooling of xenon-derivatized myoglobin crystals

A method for preparing cryocooled xenon-derivatized protein crystals is presented.

The effect of laboratory magnetic fields on neutron reflection

It is shown how neutron reflectivity is altered when magnetic field gradients are present along the neutron path.

A novel technique to control the rate of vapour diffusion, giving larger protein crystals

A simple technique for improving the size of protein crystals by controlling the rate of vapour-diffusion trials is presented.

On the use of the merging R factor as a quality indicator for X-ray data

By comparison of the accuracy and the merging R factor (R_merge) of artificially created X-ray data sets, it is demonstrated that R_merge is a poor predictor for the precision of X-ray data. The more often a given reflection is observed, the more precise the average intensity is, whereas R_merge has a tendency to be higher at higher data redundancy.

MAINDEX – manual indexation for area-detector crystallographic data

A program for the manual indexation of area-detector data is presented.

POTATO – a program for generating perovskite structures distorted by tilting of rigid octahedra

A program that, given the tilt system, tilt angles and octahedral bond distances, will calculate the ideal crystal structure for AMO₃ and A₂MM'O₆ perovskites distorted by octahedral tilting is presented.

See the Journal of Applied Crystallography Software List 1997.

DEBVIN – a program for Rietveld refinement with generalized coordinates subjected to geometrical restraints

DEBVIN is a program that combines the Rietveld approach with the use of generalized coordinates. It is a particularly useful tool when, as in polymer crystallography, structures are rather complex and diffraction patterns highly overlapped and confined to low diffraction angles. Refinement of crystallite dimensions is also a qualifying feature of this program.

See the Journal of Applied Crystallography Software List 1997.

Crystallographers

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Structural electron crystallography by D. Dorset

Symmetry in chaos by M. Field and M. Golubitsky

Metallomesogens - synthesis, properties and applications edited by L. Serrano

Ordering and phase transitions in charged colloids edited by A. K. Arora and B. V. R. Tata