Foundations of Crystallography

 

Acta Cryst. (2008). A64, 601-612  [ doi:10.1107/S0108767308022149 ]

How to multiply a matrix of normal equations by an arbitrary vector using FFT

B. V. Strokopytov

Synopsis: A novel full-matrix technique for crystallographic macromolecular refinement is described.

Online 7 October 2008

 

Acta Cryst. (2008). A64, 613-624  [ doi:10.1107/S0108767308024574 ]

Elastic scattering of high-energy electrons by dopant atoms within a crystal in transmission electron microscopy

B. G. Mendis

Synopsis: A Bloch-wave model that predicts electron scattering by a dopant atom is derived using perturbation theory. The results are largely confirmed by multislice simulations but subtle differences have also been observed and are attributed to the approximations made in the Bloch-wave model.

Online 7 October 2008

 

Acta Cryst. (2008). A64, 625-630  [ doi:10.1107/S0108767308027554 ]

Retrieving low- and medium-resolution structural features of macromolecules directly from the diffraction intensities - a real-space approach to the X-ray phase problem

W.-P. Su

Synopsis: A simple mathematical algorithm is proposed to generate electron-density maps directly from the X-ray diffraction intensities. The maps can reveal the internal structures of macromolecules.

Online 7 October 2008

 

Acta Cryst. (2008). A64, 631-640  [ doi:10.1107/S0108767308027591 ]

The Liga algorithm for ab initio determination of nanostructure

P. Juhás, L. Granlund, P. M. Duxbury, W. F. Punch and S. J. L. Billinge

Synopsis: The Liga algorithm for ab initio determination of some solid-state nanostructures from length lists generated by the atomic pair distribution function is described. Results are demonstrated for ideal Lennard-Jones clusters and experimental C₆₀ data.

Online 16 October 2008

 

Acta Cryst. (2008). A64, 641-653  [ doi:10.1107/S0108767308026184 ]

Reliability of Monte Carlo simulations of disordered structures optimized with evolutionary algorithms exemplified with diffuse scattering from La_0.70(1)(Al_0.14(1)I_0.86(1))

T. Weber, A. Simon, H. Mattausch, L. Kienle and O. Oeckler

Synopsis: The reliability, reproducibility and influence of refinement parameters of evolutionary algorithm refinements of Monte Carlo simulations have been investigated in analyses of complex disorder and corresponding diffuse scattering from the compound La_0.70(1)(Al_0.14(1)I_0.86(1)). It was found that the resulting structures are qualitatively and quantitatively in good agreement independent of the strategy used. Recommendations for the best choice of the parameters are given.

Online 7 October 2008

 

Acta Cryst. (2008). A64, 654-669  [ doi:10.1107/S0108767308025440 ]

Computing with almost periodic functions

R. V. Moody, M. Nesterenko and J. Patera

Synopsis: An almost periodic function f is sampled at a finite number of points. A new method is developed for discrete computation of finite Fourier expansions of the function that are almost periodic and uniformly approximate f over its entire infinite domain.

Online 16 October 2008

 

Acta Cryst. (2008). A64, 670-674  [ doi:10.1107/S0108767308027736 ]

Extending the S-FFT direct-methods algorithm to density functions with positive and negative peaks. XIV

J. Rius and C. Frontera

Synopsis: The fast-Fourier-transform-based algorithm maximizing the direct-methods sum function S has been modified to allow the treatment of density functions with positive and negative peaks. Test calculations have been performed on single-crystal X-ray diffraction data, neutron diffraction data and intensities of superstructure reflections.

Online 16 October 2008

 

Acta Cryst. (2008). A64, 675-686  [ doi:10.1107/S0108767308028742 ]

Crystal families and systems in higher dimensions, and geometrical symbols of their point groups. I. Crystal families in five-dimensional space with two-, three-, four- and sixfold symmetries

R. Veysseyre, D. Weigel and T. Phan

Synopsis: The Weigel-Phan-Veysseyre symbols are explained and their properties are described. These symbols are then assigned to the point groups of several families of space E⁵.

Online 16 October 2008

 

Acta Cryst. (2008). A64, 687-697  [ doi:10.1107/S0108767308028766 ]

Crystal families and systems in higher dimensions, and geometrical symbols of their point groups. II. Cubic families in five- and n-dimensional spaces

D. Weigel, T. Phan and R. Veysseyre

Synopsis: The definition, properties and symbols of the iso cubic groups are given. The mono cubic crystal families of space Eⁿ are defined and listed for n = 3 to n = 7. As an application, four crystal families of space E⁵ are studied in detail.

Online 16 October 2008

 

Acta Cryst. (2008). A64, 698-700  [ doi:10.1107/S0108767308024100 ]

Bijective mapping between the eigenvalue spectrum of a Karle-Hauptman matrix and its phases

A. C. Ralph

Synopsis: Given the eigenvalue spectrum of a Karle-Hauptman matrix, the phases are uniquely determined if a carefully chosen subset is fixed.

Online 7 October 2008

 

Acta Cryst. (2008). A64, 701-702  [ doi:10.1107/S010876730803362X ]

Prices of IUCr journals

Online 16 October 2008