Journal ArticleDOI
An empirical correction for absorption anisotropy
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TLDR
A least-squares procedure is described for modeling an empirical transmission surface as sampled by multiple symmetry-equivalent and/or azimuth rotation-equ equivalent intensity measurements.Abstract:
A least-squares procedure is described for modeling an empirical transmission surface as sampled by multiple symmetry-equivalent and/or azimuth rotation-equivalent intensity measurements. The fitting functions are sums of real spherical harmonic functions of even order, ylm(− u0) + ylm(u1), 2 ≤ l = 2n ≤ 8. The arguments of the functions are the components of unit direction vectors, −u0 for the reverse incident beam and u1 for the scattered beam, referred to crystal-fixed Cartesian axes. The procedure has been checked by calculations against standard absorption test data.read more
Citations
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WinGX suite for small-molecule single-crystal crystallography
TL;DR: The category Computer Program Abstracts provides a rapid means of communicating up-to-date information concerning both new programs or systems and signi®cant updates to existing ones.
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WinGX and ORTEP for Windows: an update
TL;DR: The WinGX suite provides a complete set of programs for the treatment of small-molecule single-crystal diffraction data, from data reduction and processing, structure solution, model refinement and visualization, and metric analysis of molecular geometry and crystal packing, to final report preparation in the form of a CIF.
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Scaling and assessment of data quality
TL;DR: The various physical factors affecting measured diffraction intensities are discussed, as are the scaling models which may be used to put the data on a consistent scale and algorithms used by the CCP4 scaling program SCALA.
Journal ArticleDOI
Comparison of silver and molybdenum microfocus X-ray sources for single-crystal structure determination
TL;DR: A detailed comparison of single-crystal diffraction data collected with Ag Kα and Mo’™Kα microsources (IµS) indicates that the Ag”Kα data are better when absorption is significant.
Journal ArticleDOI
Use of intensity quotients and differences in absolute structure refinement
TL;DR: Differences and quotients can be defined using Friedel pairs of reflections and applied in refinement to enable absolute structure to be determined precisely even for light atom crystal structures.
References
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Book
International tables for X-ray crystallography
Norman Fordyce McKerron Henry,Lonsdale, Kathleen, Dame,John S. Kasper,Caroline H. MacGillavry,Gerard D. Rieck,James A. Ibers,Walter C. Hamilton +6 more
Journal ArticleDOI
International Tables for X-Ray Crystallography
TL;DR: The International Tables for X-ray Crystallography (ITC) as mentioned in this paper were published by the International Union of Crystallographers (IUC) for the first time in 1952.
Book
X-Ray Analysis and the Structure of Organic Molecules
TL;DR: In this article, crystal structure analysis and chemistry electron-density distributions in molecules geometric constraints in cyclic molecules conformational maps and space groups are discussed, as well as the results experimental aspects of x-ray analysis.
Journal ArticleDOI
A matrix‐operator approach to reflection high‐energy electron diffraction theory
TL;DR: In this paper, the amplitudes of beams reflected from a crystal surface by high-energy electrons are expressed in terms of matrix operators based on Bloch waves, and the solution is derived in the limiting case of an infinite slab and is therefore applicable to cases involving overlayers of different composition and structure.