Foundations of Crystallography

 

Acta Cryst. (1999). A55, 259-266  [ doi:10.1107/S010876739800782X ]

Application of the statistical dynamical theory to -ray diffraction experiments on low-dislocation quartz single crystals

A. Kurbakov and A. Sokolov

Synopsis: The experimental verification of the statistical dynamical theory of diffraction has been carried out by means of short-wavelength highly monochromatic -ray diffractometry. Dislocation-free silicon and low-dislocation quartz single crystals have been used as the experimental objects.

Online March 1999

 

Acta Cryst. (1999). A55, 267-273  [ doi:10.1107/S0108767398008095 ]

X-ray standing wave as a result of only the imaginary part of the atomic scattering factor

R. Negishi, T. Fukamachi and T. Kawamura

Synopsis: A study of the forms of X-ray standing waves (XSW) when the real part of the scattering factor is zero shows that the effect of the anomalous transmission and absorption are connected with the phase of the XSW.

Online March 1999

 

Acta Cryst. (1999). A55, 274-288  [ doi:10.1107/S0108767398008149 ]

Geometrical effects in diffraction analysis

N. Bernhoeft

Synopsis: The role of partial beam coherence and its interplay with finite scattering volumes in diffraction experiments is discussed. Under certain conditions, the analysis of diffraction profiles in terms of a sample response function convolved with an instrumental resolution function may fail and, further, under high absorption, new information of the source of scattering below the sample surface may become available.

Online March 1999

 

Acta Cryst. (1999). A55, 289-304  [ doi:10.1107/S0108767398008629 ]

Elastic scattering of partially coherent beams of fast electrons by a crystal with a defect

N. I. Borgardt

Synopsis: Scattering of a quasi-monochromatic electron beam by a crystal with a defect is described with the use of the mutual coherency function and the formalism of quasi-Bloch waves. As an example of applying the new approach, the LACBED patterns of a crystal with a dislocation have been simulated.

Online March 1999

 

Acta Cryst. (1999). A55, 305-313  [ doi:10.1107/S0108767398009726 ]

Chemical bonding effects in the determination of protein structures by electron crystallography

S. Chang, T. Head-Gordon, R. M. Glaeser and K. H. Downing

Synopsis: Formation of bonds between atoms shifts the electron distribution from that of the free atoms, thus changing the Coulomb potential. The consequences of this effect are investigated in the context of electron crystallography of proteins, where chemical bonding effects are shown to significantly increase R factors that are calculated using free-atom scattering factors.

Online March 1999

 

Acta Cryst. (1999). A55, 314-321  [ doi:10.1107/S0108767398009982 ]

The probability distribution of structure factors with non-integral indices. II. The P1 case

C. Giacovazzo, D. Siliqi, B. Carrozzini, A. Guagliardi and A. Grazia Moliterni

Synopsis: The probability distribution of structure factors with non-integral indices is derived in P1.

Online March 1999

 

Acta Cryst. (1999). A55, 322-331  [ doi:10.1107/S0108767398009994 ]

The probability distribution function of structure factors with non-integral indices. III. The joint probability distribution in the P1 case

C. Giacovazzo, D. Siliqi, A. Altomare, G. L. Cascarano, R. Rizzi and R. Spagna

Synopsis: Joint probability distribution functions of structure factors with rational indices are derived in P1. Phase relationships are obtained.

Online March 1999

 

Acta Cryst. (1999). A55, 332-341  [ doi:10.1107/S0108767398010009 ]

Enumeration of four-connected three-dimensional nets. I. Conversion of all edges of simple three-connected two-dimensional nets into crankshaft chains

S. Han and J. V. Smith

Synopsis: 57 three-dimensional nets were obtained by converting into crankshaft chains all edges of the simpler two-dimensional nets in the catalog of the Consortium of Theoretical Frameworks; nine occur in known structures.

Online March 1999

 

Acta Cryst. (1999). A55, 342-359  [ doi:10.1107/S0108767398010010 ]

Enumeration of four-connected three-dimensional nets. II. Conversion of edges of three-connected 2D nets into zigzag chains

S. Han and J. V. Smith

Synopsis: 138 3D nets were generated by converting some horizontal edges of three-connected 2D nets into zigzag chains, and 19 of them are represented by known structures.

Online March 1999

 

Acta Cryst. (1999). A55, 360-382  [ doi:10.1107/S0108767398010022 ]

Enumeration of four-connected three-dimensional nets. III. Conversion of edges of three-connected two-dimensional nets into saw chains

S. Han and J. V. Smith

Synopsis: Seven of the 175-plus three dimensional nets based on parallel saw chains occur in known structures: edingtonite, `nepheline hydrate', offretite, Linde Type L, ATT, SZF and ZST.

Online March 1999

 

Acta Cryst. (1999). A55, 383-395  [ doi:10.1107/S0108767398010186 ]

Algorithms for deriving crystallographic space-group information

R. W. Grosse-Kunstleve

Synopsis: Algorithms are presented for three-dimensional crystallographic space groups, handling tasks such as generation of symmetry operations, the characterization of symmetry operations, the determination of space-group type and the generation of structure-seminvariant vectors and moduli.

Online March 1999

 

Acta Cryst. (1999). A55, 396-398  [ doi:10.1107/S0108767398009167 ]

Probability distribution of the four-phase structure invariants of isomorphously related structure factors and its applications

Y. S. Liu, N. H. Hu and S. Y. Wang

Synopsis: A formula for the estimation of four-phase structure invariants involving four pairs of isomorphously related structure factors is described.

Online March 1999

 

Acta Cryst. (1999). A55, 399  [ doi:10.1107/S0108767398016900 ]

Electron microscopy 1998

Online March 1999