Acta Crystallographica Section A

Foundations of Crystallography

Volume 53, Part 6 (November 1997)

Cover illustration: A structural model of the decagonal Al-Pd-Mn quasicrystal, which consists of clusters represented by decagons and ten pentagons surrounding each decagon. This is obtained from a periodic structure in five-dimensional space by taking a three-dimensional section. Courtesy of A. Yamamoto.

• research papers
• short communications
• international union of crystallography
• book reviews
• books received

research papers

Acta Cryst. (1997). A53, 749-762    [doi:10.1107/S0108767397004558]

Relativistic X-ray Elastic Scattering Factors for Neutral Atoms Z = 1-54 from Multiconfiguration Dirac-Fock Wavefunctions in the 0-12Å^-1 sin / Range, and Six-Gaussian Analytical Expressions in the 0-6Å^-1 Range

Z. Su and P. Coppens

Synopsis: X-ray elastic scattering factors for ground-state neutral atoms (H through Xe) have been calculated from the relativistic multiconfiguration Dirac-Fock wavefunctions. The results have been fitted to six-Gaussian analytical expressions for the sin/ ranges of 0-2, 2-4 and 4-6Å^-1. The atomic energies and second moments are also presented.

Acta Cryst. (1997). A53, 763-771    [doi:10.1107/S0108767397004595]

The Optical Activity of Crystalline L-Aspartic Acid

T. Asahi, M. Takahashi and J. Kobayashi

Synopsis: All the components of gyration tensor and birefringence of L-aspartic acid have been successfully measured as a function of the temperature. It is of special interest that the chirality index of aspartic acid was found to be almost the same as that of glutamic acid.

Acta Cryst. (1997). A53, 772-780    [doi:10.1107/S010876739700737X]

Grain Boundaries as Projections from Higher-Dimensional Lattices

J. L. Aragón, D. Romeu, L. Beltrán and A. Gómez

Synopsis: Points of best fit between pairs of lattices are found using higher-dimensional lattices. It constitutes a generalization of the coincidence lattice.

Acta Cryst. (1997). A53, 781-788    [doi:10.1107/S0108767397008659]

Application of Grazing-Angle X-ray Standing Waves to the In-Plane Structure of a 100Å-Thick Epilayer Film

O. Sakata and H. Hashizume

Synopsis: Dynamical diffraction in an epilayer crystal, as thin as 100Å, is shown to modify significantly the field pattern of grazing-angle X-ray standing waves produced by the substrate. The technique is applied to the determination of the registration and the ordering of a Ca_0.39Sr_0.61F₂ epilayer on GaAs (111).

Acta Cryst. (1997). A53, 789-798    [doi:10.1107/S0108767397009653]

Improving Direct-Methods Phases by Heavy-Atom Information and Solvent Flattening

C. Giacovazzo and D. Siliqi

Synopsis: Phases obtained by direct methods are improved by using information on the heavy-atom structure and a suitable solvent-flattening technique.

Acta Cryst. (1997). A53, 799-806    [doi:10.1107/S0108767397009665]

The Translation Problem in Molecular Replacement Techniques. II. The Estimate of Quartet Invariants

C. Giacovazzo, L. Manna and D. Siliqi

Synopsis: The probabilistic estimate of quartet invariants is obtained when prior information on well oriented molecular fragments is available.

short communications

Acta Cryst. (1997). A53, 807-808    [doi:10.1107/S0108767397009781]

Alternative formulae for the number of sublattices

B. Gruber

Synopsis: Two formulae for the number of sublattices of a given index k of an n-dimensional lattice are presented which give the result in a considerably quicker way than any previous method.

Acta Cryst. (1997). A53, 809    [doi:10.1107/S0108767397010325]

Metric properties of the root-mean-square deviation of vector sets

K. Kaindl and B. Steipe

Synopsis: A proof is given that the root-mean-square deviation between more than two vector sets after optimal superposition induces a metric.

Acta Cryst. (1997). A53, 810-812    [doi:10.1107/S0108767397010374]

Additional comments on the theoretical formulation of X-ray moiré fringes

J. Yoshimura

Synopsis: A previous theoretical formulation of X-ray moiré fringes for a bicrystal model is explained to clarify the meanings of the formulation.

Acta Cryst. (1997). A53, 813    [doi:10.1107/S0108767397010891]

A detailed observation of the nonprojectiveness of X-ray moiré-fringed diffraction images. Erratum

J. Yoshimura

Synopsis: Erratum to Acta Cryst. (1996), A 52, 312-325.

international union of crystallography

Acta Cryst. (1997). A53, 814-852    [doi:10.1107/S0108767397099807]

Report of the Executive Committee for 1996

Acta Cryst. (1997). A53, 853-854    [doi:10.1107/S0108767397099790]

Prices of IUCr journals

book reviews

Acta Cryst. (1997). A53, 855    [doi:10.1107/S0108767397099789]

Organic molecular crystals: interaction, localization and transport phenomena by E. A. Silinsh and V. Cápek

Acta Cryst. (1997). A53, 855-856    [doi:10.1107/S0108767397099777]

Physics and chemistry at oxide surfaces by C. Noguera

books received

Acta Cryst. (1997). A53, 856    [doi:10.1107/S0108767397099765]

Collected works of Dorothy Crowfoot Hodgkin. Vol. I. Insulin. Vol. II. Cholestrol, penicillin and other antibiotics. Vol. III. General crystallography and essays edited by G. G. Dodson, J. P. Glusker, S. Ramaseshan and K. Venkatesan

Acta Cryst. (1997). A53, 856    [doi:10.1107/S0108767397099753]

Synchrotron radiation techniques in industrial, chemical, and materials science edited by K. L. D'Amico, L. J. Terminello and D. K. Shuh

Acta Cryst. (1997). A53, 856    [doi:10.1107/S0108767397099741]

X-ray and neutron dynamical diffraction, theory and applications edited by A. Authier, S. Lagomarsino and B. K. Tanner

Acta Cryst. (1997). A53, 857-859

Subject index to volume A53 (1997)

Acta Cryst. (1997). A53, 860-863

Author index to volume A53 (1997)

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