Journal of Applied Crystallography

Volume 33, Part 2 (April 2000)

	Cover illustration: Reorientation pathways of the octahedral PF6 anion in KPF6, calculated by an evolution algorithm. Courtesy of K. Knorr (University Kiel, Earth Sciences - Mineralogy) and Fritz Mädler (HMI Berlin) [J. Appl. Cryst. (1999), 32, 902-910].

• research papers
• teaching and education
• short communications
• computer programs
• laboratory notes
• computer program abstracts
• addenda and errata
• meetings

research papers

J. Appl. Cryst. (2000). 33, 201-205  [ doi:10.1107/S0021889899014739 ] X-ray study of the light-induced metastable state of a spin-crossover compound J. Kusz, H. Spiering and P. Gütlich Synopsis: Iron(II) complexes exhibiting thermal spin crossover may be converted from the 1A1 low-spin state to the 5T2 high-spin state by irradiation with green light (light-induced excited spin-state trapping, LIESST). The lifetime of the metastable LIESST state may be sufficiently long for X-ray diffraction study. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 206-212  [ doi:10.1107/S0021889899014879 ] A non-linear positive method to reconstruct the parent textures from the inherited textures in phase transformation M. Humbert, N. Gey and C. Esling Synopsis: A non-linear positive method to reconstruct the parent textures from the inherited textures in phase transformation is presented. Its efficiency to reconstruct the parent textures even if small variant selection occurred is illustrated with numerical examples. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 213-217  [ doi:10.1107/S0021889899014922 ] X-ray investigation and discussion of the magnetostriction of Gd3T (T = Ni, Rh, Irx) single crystals J. Kusz, H. Böhm and E. Talik Synopsis: The variations of the lattice parameters with temperature and anomalous anisotropic spontaneous magnetostriction of Gd3T single crystals were measured in the range 10-300 K. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 218-225  [ doi:10.1107/S0021889899015216 ] SAXS experiments on absolute scale with Kratky systems using water as a secondary standard D. Orthaber, A. Bergmann and O. Glatter Synopsis: SAXS experiments can be performed on an absolute scale with Kratky collimation systems using water as a secondary standard. The necessary basic equations are summarized and two examples demonstrate the performance of the method. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 226-233  [ doi:10.1107/S0021889899015484 ] Elimination of extrinsic components overlapping lattice distortion variations of a silicon single crystal obtained by double-crystal X-ray topography Y. Kudo, K.-Y. Liu, S. Kawado and K. Hirano Synopsis: The new sample-rotation and area-detector-traverse method using X-ray optics for double-crystal X-ray topography was developed in order to measure variations in lattice distortion, free of extrinsic components, of an as-grown silicon single crystal. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 234-242  [ doi:10.1107/S0021889899015654 ] Next-near-neighbour interactions with Al in Li+- and Rb+-exchanged Na+ -aluminas, detected by synchrotron X-ray absorption spectroscopy A. Marcelli, A. Mottana and G. Cibin Synopsis: Synchrotron X-ray absorption near-edge structure (XANES) spectroscopy studies have been carried out on the electronic and crystal structure environments of the Al atom in Na+ -alumina and in two -aluminas with Na+ exchanged by Li+ and Rb+. The aim is to define the type of interaction, if any, existing between the Al located in the `spinel block' and the fast-conducting cations in the `conduction plane'. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 243-251  [ doi:10.1107/S0021889899015666 ] Multiple CCD detector for macromolecular X-ray crystallography W. C. Phillips, M. Stanton, A. Stewart, H. Qian, C. Ingersoll and R. M. Sweet Synopsis: A 20 × 20 cm CCD-based X-ray detector designed for macromolecular crystallography is described. Measurements of performance and crystallographic data collected with synchrotron radiation are presented. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 252-258  [ doi:10.1107/S0021889899016039 ] Refinement of free structure parameters of a thin film when only one reflection is available D. C. Meyer and P. Paufler Synopsis: Taking a Ga0.5In0.5P/(001)GaAs epilayer as an example, it is found that the energy dependence of diffraction anomalous fine structure (DAFS) intensity is still sufficiently sensitive to structure parameters when the oscillating part is neglected. One reflection may already yield satisfactory data. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 267-278  [ doi:10.1107/S002188989901643X ] Accuracy of XRPD QPA using the combined Rietveld-RIR method A. F. Gualtieri Synopsis: The accuracy of the estimate of the weights calculated from the quantitative phase analysis (QPA) of complex mixtures which contain zeolites and clays using the combined Rietveld and reference intensity ratio (RIR) methods is assessed. The influence of fundamental factors, such as the choice of the structure model, the amount of added internal standard and the displacement parameters, is considered. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 279-284  [ doi:10.1107/S0021889899016659 ] Phase transitions in ReO3 studied by high-pressure X-ray diffraction J.-E. Jørgensen, J. Staun Olsen and L. Gerward Synopsis: A new monoclinic ReO3 phase has been observed in the pressure range 3-12 GPa by energy-dispersive X-ray powder diffraction. ReO3 was shown to be rhombohedral above 12 GPa Online 1 April 2000

J. Appl. Cryst. (2000). 33, 285-290  [ doi:10.1107/S0021889899016830 ] Small-angle X-ray scattering analysis of the periodic tricontinuous network structure of symmetric ABC triblock copolymers M. Seki, J. Suzuki and Y. Matsushita Synopsis: The periodic tricontinuous network structure (TNS) of symmetric isoprene-styrene-2-vinylpyridine triblock copolymers has been studied by small-angle X-ray scattering (SAXS). The observed SAXS profiles were compared with the calculated diffraction intensities based on the model electron density distributions constructed for a pair of surfaces parallel to the infinite periodic minimal surface. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 291-295  [ doi:10.1107/S0021889899016829 ] Performance of a multi-wavelength monochromator system for neutron single-crystal and powder diffraction F. U. Ahmed, I. Tanaka and N. Niimura Synopsis: In order to improve significantly data collection efficiency, the advantages of using multi-wavelengths in single-crystal neutron diffraction as well as in powder neutron diffraction were established by experiments using a stacked monochromator assembly of two elastically bent perfect Si(111) and Si(220) crystals. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 296-306  [ doi:10.1107/S0021889800000133 ] X-ray diffraction analysis of stacking and twin faults in f.c.c. metals: a revision and allowance for texture and non-uniform fault probabilities L. Velterop, R. Delhez, Th. H. de Keijser, E. J. Mittemeijer and D. Reefman Synopsis: The description of line profiles from f.c.c. metals containing stacking and twin faults, as derived by Warren, has been revised and extended. It is discussed how fault probabilities can be determined from line profiles and it is shown by simulation that the revision leads to significantly better results. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 307-311  [ doi:10.1107/S0021889800000157 ] Solving crystal structures in P1: an automated procedure for finding an allowed origin in the correct space group M. C. Burla, B. Carrozzini, G. L. Cascarano, C. Giacovazzo and G. Polidori Synopsis: An automatic procedure finds an allowed origin in the actual space group when the structure is solved in P1 by direct methods. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 312-322  [ doi:10.1107/S0021889800000145 ] Assessment of different X-ray stress measuring techniques for thin titanium nitride coatings A. Saerens, P. Van Houtte, B. Meert and C. Quaeyhaegens Synopsis: The validities of the d-sin2 method, a low incident-beam-angle method and the crystallite-group method are determined for thin titanium nitride coatings, taking the crystallographic texture into account. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 323-329  [ doi:10.1107/S0021889800000686 ] Kinematical intensity profiles obtained for single and multiple diffraction in perfect spherical crystals E. Rossmanith Synopsis: Intensity profiles obtained for single and multiple diffraction are derived in the framework of the kinematical theory for a spherically shaped crystal. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 330-333  [ doi:10.1107/S0021889800000698 ] Extinction-corrected mean thickness and integral width used in the program UMWEG98 E. Rossmanith Synopsis: Expressions for the extinction-corrected mean thickness and integral width for spherical crystals suitable for use in the development of crystallographic software are discussed. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 334-337  [ doi:10.1107/S0021889800000856 ] Modeling radial collimators for use in stress and texture measurements with neutron diffraction D.-Q. Wang, X.-L. Wang, J. L. Robertson and C. R. Hubbard Synopsis: Both analytical and Monte Carlo numerical models for the calculation of the neutron transmission function in the sampling volume through a radial collimator are presented. It is shown that the transmission function is sensitive to the parameters of the collimator, particularly, the collimator length and the number of blades. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 338-343  [ doi:10.1107/S002188980000114X ] A correction for anisotropic line broadening due to structural defects in powder diffraction structure analysis L. A. Solovyov Synopsis: An approach to the problem of anisotropic line broadening due to structural defects is developed for powder diffraction structure analysis. The application of this approach in structural investigations of trans- and -trans-[Pd(NH3)2X2] (X = Cl, Br, I) overcame the problem of broadening and allowed precise and self-consistent information about the structure and microstructure of these compounds to be obtained. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 344-349  [ doi:10.1107/S0021889800001151 ] Use of a crystallization robot to set up sitting-drop vapor-diffusion crystallization and in situ crystallization screens C. F. Snook, M. D. Purdy and M. C. Wiener Synopsis: A commercial crystallization robot has been modified for use in setting up sitting-drop vapor-diffusion crystallization experiments, and for setting up protein crystallization screens in situ. The primary aim of this effort is the automated screening of crystallization of integral membrane proteins in detergent-containing solutions; however, the results of this work are of general utility to robotic liquid-handling systems. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 364-371  [ doi:10.1107/S0021889899016684 ] Application of high-energy synchrotron radiation for texture studies O. V. Mishin, E. M. Lauridsen, N. C. Krieger Lassen, G. Brückner, T. Tschentscher, B. Bay, D. Juul Jensen and H. F. Poulsen Synopsis: A novel experimental technique that employs high-energy synchrotron radiation is used for the investigation of through-thickness texture gradients in cold-rolled aluminium plates. Experimental aspects and potentials of the new technique are discussed. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 372-379  [ doi:10.1107/S0021889800000868 ] Polar potassium rare earth nitrates K2[RE(NO3)5(H2O)2] (RE = La, Ce, Pr and Nd). I. Crystal growth and crystal structures P. Held, H. Hellwig, S. Rühle and L. Bohatý Synopsis: Large single crystals (up to 5 × 5 × 4 cm ) of optical quality were grown from aqueous solutions containing a surplus of nitric acid using a standard evaporation method at 311 K. The main structural feature is the diaquapentanitratolanthanide(III) group, [RE(NO3)5(H2O)2]. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 380-386  [ doi:10.1107/S002188980000087X ] Polar potassium rare earth nitrates K2[RE(NO3)5(H2O)2] (RE = La, Ce, Pr and Nd). II. Linear and nonlinear optical properties H. Hellwig, S. Rühle, P. Held and L. Bohatý Synopsis: Using high-precision refractive indices, phase-matching conditions for second-harmonic generation have been analysed. coefficients have been determined from Maker fringe experiments and interpreted using a simple model (summing the molecular hyperpolarizabilities of the NO3 group). Online 1 April 2000

teaching and education

J. Appl. Cryst. (2000). 33, 387-388  [ doi:10.1107/S0021889899015691 ] Crystallization bench B. Cabric and T. Pavlovic Synopsis: An apparatus for preparing single crystals from the melt in a school laboratory is described. Online 1 April 2000

short communications

J. Appl. Cryst. (2000). 33, 389-391  [ doi:10.1107/S0021889899015344 ] Parallel-beam X-ray diffractometry using X-ray guide tubes T. Yamanoi and H. Nakazawa Synopsis: A parallel-beam X-ray diffraction geometry using X-ray guide tubes is proposed to eliminate preferred-orientation effects in powder X-ray diffraction (XRD) patterns and for new applications of XRD. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 392-393  [ doi:10.1107/S0021889800000777 ] How the R factor changes as molecules become larger F. C. Krebs Synopsis: The classical R factor was correlated with the number of independent atoms for structures contained in the Cambridge Structural Database. The findings have an important bearing on the R factor to be expected for a structure of a given size, in particular for large-molecule structures. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 394-396  [ doi:10.1107/S0021889800000893 ] The Huber G670 imaging-plate Guinier camera tested on beamline I711 at the MAX II synchrotron K. Ståhl Synopsis: The Huber G670 Guinier powder diffractometer provided high-quality Rietveld-refinable data in a matter of seconds using a synchrotron source. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 397-400  [ doi:10.1107/S0021889800001254 ] In situ X-ray crystallography A. McPherson Synopsis: A method is proposed, and preliminary experiments are described, for collection of X-ray data from macromolecular crystals in situ. The usual processes of mounting for either room-temperature or cryogenic X-ray data collection are eliminated by growing crystals, using vapor diffusion, on small supports or films that can be either frozen or treated before transfer directly to the X-ray beam. Online 1 April 2000

computer programs

J. Appl. Cryst. (2000). 33, 401-405  [ doi:10.1107/S0021889899013655 ] ROD: a program for surface X-ray crystallography E. Vlieg Synopsis: A brief description is given of the C-program ROD with which surface structures can be refined on the basis of X-ray data. Online 1 April 2000

J. Appl. Cryst. (2000). 33, 406-414  [ doi:10.1107/S0021889899015058 ] ShakePSD: automatic phase solver covering heavy-atom methods and direct methods for Windows PCs S. Okada and K. Okada Synopsis: ShakePSD (filtering using the Patterson function, search procedures and direct methods) is a single program for organic compounds (running under Windows on a PC). The program can discriminate whether a heavy atom is included or not and can apply direct methods (Patterson function and search for all remaining atoms) or direct methods (tangent formula and/or minimal function). Online 1 April 2000

laboratory notes

J. Appl. Cryst. (2000). 33, 415-416  [ doi:10.1107/S0021889899015587 ] A beam-stop mount designed for use with area detectors A. Bertok, J. W. Allen Jr, W. Li and S. Sheriff Synopsis: A beam-stop holder is described that allows for easy removal during alignment and calibration measurements and then for precise repositioning prior to data collection. Online 1 April 2000

computer program abstracts

addenda and errata

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