Aspects of the modelling of the radial distribution function for small nanoparticles

The structures of ZnSe and CdSe/ZnS core/shell nanoparticle samples have been studied by analysing the radial distribution functions. Methods are presented to calculate the radial distribution functions of these nanoparticle types.

A structural proteomics filter: prediction of the quaternary structural type of hetero-oligomeric proteins on the basis of their sequences

Identification of hetero-oligomeric proteins based on their amino acid sequence and implications for macromolecular crystallography are discussed.

X-ray extinction changes due to dislocations

A procedure for determination of dislocation density in weakly distorted crystals by means of X-ray extinction measurements is proposed.

In situ synchrotron powder diffraction study of active belite clinkers

The chemical reactions and transformations accompanying clinkerization have been followed in situ by X-ray synchrotron powder diffraction at temperatures between 1200 and 1700 K. All patterns have been evaluated by the Rietveld method to obtain quantitative phase analyses.

Interpretation of small-angle X-ray scattering patterns of crystalline triglyceride nanoparticles in dispersion

Dispersions of triglyceride nanocrystals exhibit complex small-angle X-ray diffraction patterns due to the occurrence of different structural features on similar length scales. A novel computer-aided data analysis method is introduced and applied successfully to SAXS patterns of phospholipid-stabilized tripalmitin nanosuspensions.

Least-squares thermal expansion tensor of vanadate and arsenate triclinic apatites derived from laboratory X-ray powder diffraction cell data

Applied to in-lab X-ray powder cell data for triclinic vanadate and arsenate apatites, a novel and simple method for the least-squares extraction of the thermal expansion tensor shows that both materials contract considerably along [24] upon heating. Reversible phase transitions observed at, respectively, 453 and 583 K are attributed to mobility of contact surfaces between triclinic twins within mosaic blocks.

Microstrain-like diffraction-line broadening as exhibited by incommensurate phases in powder diffraction patterns

Variations of lattice and modulation parameters of an incommensurately modulated phase as well as the resulting line broadening were theoretically analysed.

Application of the constrained S-FFT direct-phasing method to powder diffraction data. XIII

A simple and completely general phasing procedure (S-FFT) has been developed that maximizes the direct-methods origin-free modulus sum function S by means of the FFT algorithm. An algorithm combining the S-FFT procedure with real-space constraints according to the Shake-and-Bake philosophy is given and its capability to treat powder diffraction data is proved with some realistic test structures.

Temperature dependence of the crystal structure of α-AgSCN by powder neutron diffraction

A structural study of α-AgSCN was carried out using the neutron powder diffractometer HIPPO (high-pressure preferred orientation powder) at ten different temperatures between 25 and 275 K. α-AgSCN is unusual in that it has an ordered structure with no disorder in the orientation of the anionic ligands.

TRY, a new computer program for crystal structure analysis from diffraction data based on internal coordinates and on a molecular modelling procedure free of redundant coordinates

A program for modelling intricate molecules based on refinement of internal coordinates is described.

On the intersection of grating truncation rods with the Ewald sphere studied by grazing-incidence small-angle X-ray scattering

The precise location of the intersection of the grating truncation rods with the Ewald sphere of a grating is calculated for any azimuthal angle by grazing-incidence small-angle X-ray scattering.

A new design for the standard pinhole small-angle neutron scattering instrument D11

Monte Carlo simulations show that improved guide characteristics, a diverging trumpet at the beginning of the guide system and a converging guide at the end (maybe with a variable trumpet) promise a considerable improvement of the performance of D11 or other pinhole small-angle neutron scattering (SANS) instruments with the converging trumpet overcoming disadvantages for small collimation distances caused by the diverging trumpet. The use of a glass guide to reduce background is a good concept for SANS instruments.

Evidence for the presence of U–Mo–Al ternary compounds in the U–Mo/Al interaction layer grown by thermal annealing: a coupled micro X-ray diffraction and micro X-ray absorption spectroscopy study

This work demonstrates the very low Mo solubility in UAl₃ and UAl₄ binary phases; it contradicts the hypothesis of the formation of (U,Mo)Al₃ and (U,Mo)Al₄ often presented in the literature.

On the precision and accuracy of structural analysis of light-induced metastable states

The biases in the structural analysis of light-induced molecular metastable states are quantitatively investigated using simulated and experimental data for the spin-crossover complex [Fe(phen)₂(NCS)₂].

Application of white-beam X-ray microdiffraction for the study of mineralogical phase identification in ancient Egyptian pigments

The method of white-beam X-ray microdiffraction has been extended to obtain phase information from samples that exhibit a heterogeneous mineralogy. By indexation of the complex Laue patterns, demonstration of the white-beam methodology is applied to determine the mineralogy of colour pigments from an ancient Egyptian coffin.

In situ X-ray diffraction analysis of (CF_x)_n batteries: signal extraction by multivariate analysis

Application of multivariate analysis to in situ X-ray diffraction data sets shows great promise for extraction of weak diffraction signals. The mathematical treatment of the data set enables separation into individual components, thus enabling a more straightforward investigation of dynamic reaction behavior.

Advances in spectroscopic methods for biological crystals. 1. Fluorescence lifetime measurements

An improved version of the micro­spectro­photometer of the ESRF `Cryobench' laboratory is described, and the implementation of a fluorescence lifetime measurement system suitable for crystals or nanolitre-sized solution samples is reported.

Advances in spectroscopic methods for biological crystals. 2. Raman spectroscopy

A Raman microspectrophotometer is described that allows the investigation of protein crystals under the same experimental conditions as those used for X-ray diffraction. Examples highlight the outstanding quality of Raman spectra recorded in protein crystals under non-resonant conditions, and demonstrate the interest of the technique as a complementary tool to macromolecular crystallography.

A comparison of protein models obtained by small-angle X-ray scattering and crystallography

SAXS-based protein models can be obtained by conventional or ab initio approaches. The comparison of these models with those obtained from crystallography shows far-reaching agreement, even in the case of giant proteins.

Variable-temperature X-ray crystal structure determinations of {Fe[tren(6-Mepy)₃]}(ClO₄)₂ and {Zn[tren(6-Mepy)₃]}(ClO₄)₂ compounds: correlation of the structural data with magnetic and Mössbauer spectroscopy data

Variable-temperature X-ray crystal structure determinations (80–330 K) on {Fe[tren(6-Mepy)₃]}(ClO₄)₂ (1-Fe) and {Zn[tren(6-Mepy)₃]}(ClO₄)₂ (1-Zn) were carried out together with a detailed analysis of the unit-cell volume and parameters in the spin transition region for (1-Fe). The variation in metal–ligand bond lengths, the distortion parameters, as well as the cell parameters are very close to the character of the magnetic curve and the curve of γ_HS derived from the Mössbauer data which shows the correlation between structure and physical properties in (1-Fe).

On the role of nitrogen in stiffening the diamond structure

By a combination of synchrotron X-ray diffraction and optical studies, it is concluded that incorporation of nitrogen into natural diamond during growth stiffens the structure against plastic deformation.

Illustrated Fourier transforms for crystallography

Concepts such as Fourier transformation, convolution and resolution that are required to understand crystallography are illustrated through visual examples.

Structural investigation of the cubic perovskite-type doped lanthanum cobaltite La_0.6Sr_0.4CoO_3−δ at 1531 K: possible diffusion path of oxygen ions in an electrode material

The crystal structure of a cubic perovskite-type doped lanthanum cobaltite, La_0.6Sr_0.4CoO_3−δ, has been studied using in situ neutron powder diffraction data measured at 1531 K.

Characterization of polycapillary X-ray lens for application in confocal three-dimensional energy-dispersive micro X-ray diffraction experiments

The application of the polycapillary X-ray optics in confocal three-dimensional energy-dispersive micro X-ray diffraction experiments is studied.

GenX: an extensible X-ray reflectivity refinement program utilizing differential evolution

A program for refinement of reflectivity data using a genetic algorithm, differential evolution, is presented. The program is capable of simulating diffuse and specular X-ray reflectivity, as well as neutron reflectivity with or without magnetic contrast including spin-flip scattering.

GenOVa: a computer program to generate orientational variants

This computer program calculates the orientational variants, the operators and the composition table of a groupoid.

ARPGE: a computer program to automatically reconstruct the parent grains from electron backscatter diffraction data

A computer program has been written to reconstruct the parent grains from EBSD data of phase transition materials.

Forthcoming meetings and short courses