Journal of Applied Crystallography

 

J. Appl. Cryst. (2002). 35, 291-295  [ doi:10.1107/S0021889802002273 ]

Thermal expansion and atomic displacement parameters of cubic KMgF₃ perovskite determined by high-resolution neutron powder diffraction

I. G. Wood, K. S. Knight, G. D. Price and J. A. Stuart

Synopsis: The structure of KMgF₃ has been determined by high-resolution neutron powder diffraction at 4.2  K, room temperature and at 10  K intervals from 373  K to 1223  K, and is found to remain cubic at all temperatures. Thermal expansion was fitted using a second-order Grüneisen approximation to the zero-pressure equation of state, while the atomic displacement parameters were found to increase smoothly with temperature and could be fitted using Debye models.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 296-303  [ doi:10.1107/S0021889802002844 ]

Bridging the gap - structure determination of the red polymorph of tetrahexylsexithiophene by Monte Carlo simulated annealing, first-principles DFT calculations and Rietveld refinement

M. A. Neumann, C. Tedesco, S. Destri, D. R. Ferro and W. Porzio

Synopsis: The crystal structure of the red polymorph of tetrahexylsexithiophene is solved from X-ray powder diffraction data, using a combination of direct-space Monte Carlo simulated annealing, DFT lattice-energy minimization and Rietveld refinement.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 304-313  [ doi:10.1107/S0021889802003035 ]

Illustration of the anisotropic Porod law

S. Ciccariello, J.-M. Schneider, B. Schönfeld and G. Kostorz

Synopsis: The application of the anisotropic Porod law is illustrated for the case of ellipsoidal particles.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 314-318  [ doi:10.1107/S0021889802003692 ]

Propagation of X-ray coherence for diffraction of perfect crystals

H. Yamazaki and T. Ishikawa

Synopsis: Propagation of X-ray coherence through dynamical diffraction of a perfect crystal is discussed based on time-dependent Takagi-Taupin equations.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 319-326  [ doi:10.1107/S0021889802003837 ]

A microspectrophotometer for UV-visible absorption and fluorescence studies of protein crystals

D. Bourgeois, X. Vernede, V. Adam, E. Fioravanti and T. Ursby

Synopsis: A microspectrophotometer is described that allows one to probe protein crystals both in absorption and in fluorescence mode. The results highlight the interest in fluorescence microspectrophotometry for future studies in structural enzymology and protein dynamics.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 327-337  [ doi:10.1107/S0021889802004168 ]

Deconvolution of morphological texture from crystallographic texture data

G. Langelaan, L. Delannay, I. Verpoest and P. Van Houtte

Synopsis: It is shown that the orientation distribution of the fibres in a composite can be determined by deconvolution of the crystallographic texture of the fibre phase in the composite with the crystallographic texture internal to the fibres.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 338-346  [ doi:10.1107/S0021889802004156 ]

An analytical approximation for a size-broadened profile given by the lognormal and gamma distributions

N. C. Popa and D. Balzar

Synopsis: The size-broadened profile is modelled in terms of lognormal and gamma distributions of spherical crystallites. The method is applied to two ceria powders, which illustrates shortcomings of the current representation of the size-broadened profile in Rietveld refinement.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 347-355  [ doi:10.1107/S0021889802004351 ]

Unbiased analysis of neutron and X-ray reflectivity data by an evolution strategy

E. Politsch and G. Cevc

Synopsis: A novel free-form fit method for unbiased analysis of neutron and X-ray reflectivity data by an evolution strategy cancels out unsystematic features in scattering length density profiles, while it accentuates reliable details.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 356-359  [ doi:10.1107/S0021889802005770 ]

The correction of reflection intensities for incomplete absorption of high-energy X-rays in the CCD phosphor

G. Wu, B. L. Rodrigues and P. Coppens

Synopsis: It is shown that incomplete absorption of the X-ray beam in the phosphor of an area detector causes an incident-angle dependence of the recorded X-ray intensities.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 360-363  [ doi:10.1107/S0021889802003278 ]

Diffraction measurements from crystals under electric fields: instrumentation

R. Guillot, P. Allé, P. Fertey, N. K. Hansen and E. Elkaïm

Synopsis: An instrument for applying strong electric fields to crystal samples during diffraction measurements is described.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 364-367  [ doi:10.1107/S0021889802006027 ]

Ab initio modelling of intermetallics with CuAl₂ structure type: computed powder patterns from cell-and-type CRYSTMET entries

Y. Le Page, J. R. Rodgers and P. S. White

Synopsis: Fractional coordinates for structures with known type can be modelled from first principles to about the accuracy of coordinates in routine powder diffraction studies. Powder patterns recalculated from published X-ray cell data and ab initio atom coordinates can then be used for identification of materials just as well as those recalculated from structure results coming from routine X-ray powder studies.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 368-370  [ doi:10.1107/S0021889802002789 ]

Matching selenium-atom peak positions with a different hand or origin

G. D. Smith

Synopsis: A procedure is described that will match two or more sets of peaks or atoms related by different origins, enatiomorphs or symmetry elements.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 371-373  [ doi:10.1107/S0021889802003230 ]

WinXPRO: a program for calculating crystal and molecular properties using multipole parameters of the electron density

A. Stash and V. Tsirelson

Synopsis: WinXPRO, working under the Windows operating system, enables the calculation of crystal and molecular properties using multipole parameters of the electron density.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 374-376  [ doi:10.1107/S0021889802005782 ]

SnB version 2.2: an example of crystallographic multiprocessing

J. Rappleye, M. Innus, C. M. Weeks and R. Miller

Synopsis: The SnB interface provides users with several multiprocessing options for increasing throughput.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 377  [ doi:10.1107/S0021889802001449 ]

CALCIPOW: a program for calculating the diffraction by disordered lamellar structures

A. Plançon

Synopsis: The general formalism for diffraction by crystals containing translational or rotational stacking faults is implemented in the program CALCIPOW.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 378  [ doi:10.1107/S0021889802003412 ]

CHKSYM - a PC program that checks the symmetry properties of the unit cell and its contents

P. McArdle, P. Daly and D. Cunningham

Synopsis: A PC program that checks the symmetry properties of the unit cell and its contents has been added to the package Oscail.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 379  [ doi:10.1107/S002188980200506X ]

COPL: program for obtaining a complete list of order parameters for a group-subgroup crystalline phase transition

H. T. Stokes and D. M. Hatch

Synopsis: The aim of the program is to generate a complete list of order parameters, both primary and secondary, associated with a given group-subgroup pair of space groups.

Online 16 May 2002

 

J. Appl. Cryst. (2002). 35, 380  [ doi:10.1107/S0021889802006805 ]

Deane K. Smith (1930-2001)

Online 16 May 2002