Journal of Applied Crystallography

Volume 32, Part 2 (April 1999)

Cover illustration: Simulated diffraction pattern for a two-dimensionally disordered decasil (porous SiO2) calculated using a fast recursive algorithm. The plane is perpendicular to c with the reciprocal index l = 1; the error probability is 0.5 and the intensities are scaled to 25% of the highest value. Courtesy of Peter Daniels.

• research papers
• teaching and education in crystallography
• short communications
• computer programs
• laboratory notes
• computer program abstracts
• crystallographers
• book reviews
• books received
• new commercial products
• forthcoming meetings and short courses.

research papers

J. Appl. Cryst. (1999). 32, 143-153    [doi:10.1107/S0021889898005159]

Influence of miscut on crystal truncation rod scattering

A. Munkholm and S. Brennan

Synopsis:

The effect of miscut on the intensity and direction of X-ray crystal truncation rod (CTR) scattering is presented for both simple cubic and diamond cubic lattices. Data collection schemes are presented for correctly measuring the CTR intensity of a crystal with miscut.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 154-159    [doi:10.1107/S0021889898007997]

White-beam topography of Rayleigh waves: a numerical study

V. Mocella and Y. Epelboin

Synopsis:

The contrast of white-beam stroboscopic synchrotron topographs of Rayleigh waves induced by a piezoelectric transducer in an -quartz crystal is analysed. A periodic optimal thickness is found that maximizes the film contrast.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 160-167    [doi:10.1107/S0021889898008826]

Polycapillary X-ray optics for microdiffraction

C. A. MacDonald, S. M. Owens and W. M. Gibson

Synopsis:

Use of the recently developed polycapillary optics technology to collimate and focus X-ray beams provides significant benefits, including increased signal, high-energy background rejection and convenience of alignment, for diffraction with spatial resolution of the order of tens of micrometres or from small samples.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 168-173    [doi:10.1107/S0021889898010632]

A new Cu K₂-elimination algorithm

C. Dong, H. Chen and F. Wu

Synopsis:

A new algorithm for Cu K₂ elimination is presented based on the Cu K emission spectrum obtained by monolithic double-crystal spectrometer measurement.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 174-177    [doi:10.1107/S002188989801098X]

Effect of pressure on phase transitions in K_1-xNa_xMnF₃ (x = 0.04)

S. Åsbrink, A. Waskowska, H. G. Krane, L. Gerward and J. S. Olsen

Synopsis:

Synchrotron X-ray single-crystal diffraction has been used to study the pressure-induced sequence of phase transitions in potassium sodium fluoromanganate.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 178-186    [doi:10.1107/S0021889898011157]

Combination of energy minimizations and rigid-body Rietveld refinement: the structure of 2,5-dihydroxybenzo[de]benzo[4,5]imidazo[2,1-a]isoquinolin-7-one

M. U. Schmidt and R. E. Dinnebier

Synopsis:

The crystal structure of the yellow pigment C₁₈H₁₀N₂O₃ was determined from powder data by a combination of energy minimizations and rigid-body Rietveld refinement.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 187-192    [doi:10.1107/S0021889898011248]

Synchrotron radiation topographic observation of KTiOPO₄ crystals under an electric field

W. J. Liu, S. S. Jiang, Y. Ding, X. S. Wu, J. Y. Wang, X. B. Hu and J. H. Jiang

Synopsis:

In situ white-beam synchrotron radiation topographic observations under an electric field have been made on the KTiOPO₄ family of crystals. The quasi-one-dimensional conductivity is a governing factor in the explanation of the field-related phenomena.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 193-196    [doi:10.1107/S0021889898011546]

Towards general diffractometry. II. Unrestricted normal-beam equatorial geometry

P. Dera and A. Katrusiak

Synopsis:

A normal-beam equatorial four-circle diffractometer with no restrictions on its (equivalent to of Eulerian cradle and to of a cradle), and axes is described. The mathematical formalism eliminates possible misalignments of the goniometer axes.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 197-209    [doi:10.1107/S0021889898011790]

Small-angle scattering of interacting particles. II. Generalized indirect Fourier transformation under consideration of the effective structure factor for polydisperse systems

B. Weyerich, J. Brunner-Popela and O. Glatter

Synopsis:

The generalized indirect Fourier transformation method is a new technique for the evaluation of small-angle scattering data from semi-dilute or dense systems. In this contribution, the influence of polydispersity is considered by using an effective structure factor.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 210-217    [doi:10.1107/S0021889898011923]

Topological analysis of experimental electron densities

M. Souhassou and R. H. Blessing

Synopsis:

Computer algorithms for the topological analysis of experimental electron densities, mapping of the gradient and Laplacian, and search and analysis of the critical points are presented.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 218-225    [doi:10.1107/S0021889898011935]

Correction of diffraction optics and P-V-T determination using thermoelastic equations of state of multiple phases

Y. Zhao, R. B. Von Dreele and D. J. Weidner

Synopsis:

A method to determine experimental P-V-T data and to correct misalignment of diffraction optics using thermoelastic equations of state of multiple phases is presented. This technique is crucial for experiments conducted under the extreme conditions of high pressures, high temperatures and dynamic reactions.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 226-233    [doi:10.1107/S0021889898011996]

Morphological characterization of ion-sputtered C-Ag, C/C-Ag and Ag/C films by GISAXS

D. Babonneau, A. Naudon, D. Thiaudière and S. Lequien

Synopsis:

The grazing-incidence small-angle X-ray scattering (GISAXS) technique was used to analyse the morphological structure of a C-Ag co-sputtered thin film depending on the depth. A comparison of the results with those for C/C-Ag and Ag/C thin films is presented.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 234-240    [doi:10.1107/S0021889898012151]

Grazing-incidence X-ray diffraction in the study of metallic clusters buried in glass obtained by ion implantation

F. d'Acapito and F. Zontone

Synopsis:

Structural characterization of metallic clusters in ion-implanted glasses using synchrotron radiation grazing-incidence X-ray diffraction is reported.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 241-252    [doi:10.1107/S0021889898012485]

Crystalline and microstructure study of the AlN-Al₂O₃ section in the Al-N-O system. I. Polytypes and -AlON spinel phase

P. Tabary and C. Servant

Synopsis:

The crystalline and microstructure of some phases of the pseudobinary AlN-Al₂O₃ system are discussed, with special attention to the spinel phase. X-ray and neutron diffraction Rietveld peak-profile refinement data have been employed in the analysis of different hypotheses of the structures.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 253-272    [doi:10.1107/S0021889898012497]

Crystalline and microstructure study of the AlN-Al₂O₃ section in the Al-N-O system. II. '- and -AlON spinel phases

P. Tabary and C Servant

Synopsis:

Results from the crystalline and microstructure study of the ' and -AlON spinel phases by X-ray diffraction, neutron diffraction and standard-resolution transmission electron microscopy techniques are reported. A structural model is proposed to account for the double modulation of conformation and displacement of the cations and anions for the two phases.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 273-280    [doi:10.1107/S0021889898012539]

Investigation of particle size distribution and aggregate structure of various ferrofluids by small-angle scattering experiments

D. Eberbeck and J. Bläsing

Synopsis:

Size distribution and aggregation of particles in ferrofluids were quantitatively determined by means of small-angle scattering.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 281-289    [doi:10.1107/S0021889898006001]

Phenomenological model of anisotropic peak broadening in powder diffraction

P. W. Stephens

Synopsis:

A model is developed for anisotropic peak broadening in powder diffraction spectra based on the moments of the multi-dimensional distribution of lattice metrics. The technique is illustrated with two examples: sodium p-hydroxybenzoate and rubidium fulleride.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 290-295    [doi:10.1107/S0021889898012710]

The dislocation model of strain anisotropy in whole powder-pattern fitting: the case of an Li-Mn cubic spinel

T. Ungár, M. Leoni and P. Scardi

Synopsis:

Anisotropic strain broadening in a cubic Li-Mn spinel has been interpreted by the dislocation model of the mean-square strain. Combination of this dislocation model with the Fourier coefficients method enabled excellent whole powder-pattern fitting.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 296-299    [doi:10.1107/S0021889898012801]

Crystal structures and voids in diesel waxes

A. R. Gerson, S. C. Nyburg and A. McAleer

Synopsis:

Diesel waxes crystallize in one of two orthorhombic space groups: (low disorder) or Fmmm (high disorder). From the 00l spacings it is possible to calculate the extent of voids in the wax crystals.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 300-308    [doi:10.1107/S0021889898013387]

Secondary extinction in textured films

V. Yamakov and I. Tomov

Synopsis:

A method is developed for precise evaluation of pole density and secondary extinction in films. Its validity in general covers all fine-crystalline textures, whatever their origin.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 309-321    [doi:10.1107/S0021889898013399]

Diffuse X-ray scattering by 2,3-dimethylnaphthalene

R. Schreier and J. Kalus

Synopsis:

The diffuse intensity distribution of X-rays scattered from a dipolarly disordered single crystal of 2,3-dimethylnaphthalene has been measured. Correlation coefficients characterizing the mean mutual orientation of neighbouring molecules were determined.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 322-326    [doi:10.1107/S0021889898014071]

Quantitative treatment for extracting coherent elastic scattering from X-ray scattering experiments

K. Laaziri, J. L. Robertson, S. Roorda, M. Chicoine, S. Kycia, J. Wang and S. C. Moss

Synopsis:

A procedure for separating the inelastic and elastic contributions to the total scattering in high-energy scattering experiments is described. The procedure uses curve fitting of energy-dispersive X-ray spectra and is applied to scattering from amorphous silicon.

Online 1 April 1999

teaching and education in crystallography

J. Appl. Cryst. (1999). 32, 327-331    [doi:10.1107/S0021889898011169]

Crystallographic CourseWare

M. E. Kastner

Synopsis:

The software described uses animations and interactive programs to teach crystal growth, plane- and space-group symmetry elements, unit cells and asymmetric units, reciprocal space, precession photographs and an introduction to reading the International Tables for Crystallography.

Online 1 April 1999

short communications

J. Appl. Cryst. (1999). 32, 332-335    [doi:10.1107/S0021889898016161]

Automatic determination of diffuse-peak positions and the centre of a diffraction pattern

S. J. Wilkinson and D. W. L. Hukins

Synopsis:

Correlation, with a two-dimensional Gaussian function, was used to locate the positions of diffuse peaks in X-ray diffraction patterns of oriented collagen. The centre of each pattern was found by convolution with a two-dimensional Gaussian function.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 336-338    [doi:10.1107/S0021889898018366]

Making the most of commercial sparse-matrix protein crystallization screening kits

A. Albert and M. Martínez-Ripoll

Synopsis:

A rational strategy and a computer program to discern the solubility properties of a macromolecular sample are presented. The method uses the most popular crystallization screening kits.

Online 1 April 1999

computer programs

J. Appl. Cryst. (1999). 32, 339-340    [doi:10.1107/S0021889898007729]

EXPO: a program for full powder pattern decomposition and crystal structure solution

A. Altomare, M. C. Burla, M. Camalli, B. Carrozzini, G. L. Cascarano, C. Giacovazzo, A. Guagliardi, A. G. G. Moliterni, G. Polidori and R. Rizzi

Synopsis:

EXPO is a program for full powder pattern decomposition, crystal structure solution and phase refinement.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 341-344    [doi:10.1107/S0021889898010279]

VALMAP2.0: contour maps using the bond-valence-sum method

J. González-Platas, C. González-Silgo and C. Ruiz-Pérez

Synopsis:

A new version of the program VALMAP for drawing contour maps using the bond-valence-sum method is presented.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 345-350    [doi:10.1107/S0021889898011170]

AXES1.9: new tools for estimation of crystallite size and shape by Williamson-Hall analysis

H. Mändar, J. Felsche, V. Mikli and T. Vajakas

Synopsis:

Complicated analyses of X-ray powder diffraction peak shape on the bases of peak fitting, the Voigt method and the Williamson-Hall plot are implemented in the form of user-friendly dialogues into an MS-DOS program. The tools are used for the estimation of apparent (X-ray) crystallite size and lattice strain, as well as the calculation of actual dimensions of crystallites, assuming spherical or cylindrical shape.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 351-352    [doi:10.1107/S0021889898012667]

LAYER - a computer program for the graphic display of intensity data as simulated precession photographs

L. J. Barbour

Synopsis:

A computer program for the display of intensity data as simulated precession photographs is described.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 353-354    [doi:10.1107/S0021889898012679]

SECTION - a computer program for the graphic display of cross sections through a unit cell

L. J. Barbour

Synopsis:

A computer program for the display of cross-sectional slices through a unit cell is described.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 355-361    [doi:10.1107/S0021889898014472]

UMWEG-98: a program for calculation and graphical representation of multiple diffraction patterns

E. Rossmanith

Synopsis:

UMWEG-XX is a software tool for taking into account multiple diffraction effects in crystal structure analysis.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 362-364    [doi:10.1107/S0021889898017221]

MESO - a program to convert X-ray diffraction data from angular to reciprocal space

K. R. Locherer, A. Buckley and E. K. H. Salje

Synopsis:

A program has been written to convert X-ray diffraction data, generated by Siemens and INEL detectors, to reciprocal space. The application of the program to diffuse scattering in Al-doped YBCO superconductor and WO₃ is presented.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 365-368    [doi:10.1107/S0021889898015052]

FINDNCS: a program to detect non-crystallographic symmetries in protein crystals from heavy-atom sites

G. Lu

Synopsis:

A computer program to detect non-crystallographic symmetry in protein crystals from heavy-atom sites is presented. The program has been successfully applied in the determination of at least eight protein structures.

Online 1 April 1999

laboratory notes

J. Appl. Cryst. (1999). 32, 369-372    [doi:10.1107/S0021889898011662]

X-ray design constraints for in situ electrochemical cells: importance of window material, electrolyte and X-ray wavelength

A. H. Nahlé, F. C. Walsh, C. Brennan and K. J. Roberts

Synopsis:

The design of in situ electrochemical cells for X-ray absorption and diffraction studies requires attention to the window material. X-ray absorption values are calculated for a range of common polymer window materials.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 373-374    [doi:10.1107/S0021889898011674]

A strengthened zero-scattering-alloy pressure cylinder for neutron powder diffraction

K. Knorr, B. Annighöfer and W. Depmeier

Synopsis:

A modified design for zero-scaling pressure cylinders for neutron powder diffraction is described. It allows the elastic pressure capability of the cylinders to be increased.

Online 1 April 1999

computer program abstracts

J. Appl. Cryst. (1999). 32, 375    [doi:10.1107/S0021889898011510]

Java applets for crystallography

S. Weber

Synopsis:

Some crystallographic software utilities in the form of Java applets are presented.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 375-376    [doi:10.1107/S0021889898014149]

PATTERN: a precession simulation program for displaying reciprocal-space reflection data

G. Lu

Synopsis:

A program to simulate precession photographs is presented.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 376-377    [doi:10.1107/S0021889898011522]

Tcl/Tk-based programs. III. CRITXPL: graphical analysis of the X-PLOR refinement log files

L. M. Urzhumtseva and A. G. Urzhumtsev

Synopsis:

CRITXPL is a program for presenting graphically the variation of the criteria during an X-PLOR refinement.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 377    [doi:10.1107/S0021889898015362]

TOPOS3.1 - program package for multipurpose geometrical and topological analysis of crystal structures

V. A. Blatov, A. P. Shevchenko and V. N. Serezhkin

Synopsis:

The basic resources of the program package TOPOS intended for the automation of crystal-chemical analysis are described.

Online 1 April 1999

crystallographers

J. Appl. Cryst. (1999). 32, 377-378    [doi:10.1107/S0021889898018408]

1999 ICDD Crystallography Scholarship Recipients are Announced

Online 1 April 1999

book reviews

J. Appl. Cryst. (1999). 32, 378-379    [doi:10.1107/S0021889898017142]

Advanced computing in electron microscopy.

Online 1 April 1999

books received

J. Appl. Cryst. (1999). 32, 379    [doi:10.1107/S0021889898012552]

Group III nitride semiconductor compounds. Physics and applications.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 379    [doi:10.1107/S0021889898012205]

Scanning probe microscopy of polymers.

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 379    [doi:10.1107/S0021889899003751]

Disperse systems.

Online 1 April 1999

new commercial products

J. Appl. Cryst. (1999). 32, 379    [doi:10.1107/S0021889899003878]

Portable xenon pressure chamber

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 379-380    [doi:10.1107/S0021889899004124]

Crystallographica Search-Match

Online 1 April 1999

J. Appl. Cryst. (1999). 32, 0

forthcoming meetings and short courses.

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