Digitale Medien
New York, NY
:
Wiley-Blackwell
Journal of Electron Microscopy Technique
13 (1989), S. 98-110
ISSN:
0741-0581
Schlagwort(e):
Electron diffraction
;
Crystal structure determination
;
Structure factor
;
CBED
;
Life and Medical Sciences
;
Cell & Developmental Biology
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Allgemeine Naturwissenschaft
Notizen:
Convergent-beam electron diffraction provides more precise measurements of diffracted intensity than the traditional method of selected-area diffraction. The intensity is recorded at well-defined beam directions for each reflection in the pattern within disks defined by the incident cone of rays. Measurements relating to structure factors or parameters can be arranged in different ways: intensities at the zone axis position; Kossel line profiles or integrated intensities across Kossel lines; conditions for vanishing contrast at a Kossel line (e.g., critical voltage); separation between Kossel line segments at intersections. Examples of application to refinement of structure parameters (zone axis intensities) and structure factor determination (Kossel line methods) are given.The relation of these magnitudes to theory is discussed, especially for the Kossel line methods. These are described in terms of effective Fourier potentials or gaps at the Bloch-wave dispersion surface. Use of the methods for refinement of structure parameters and structure factors is reviewed with special attention to recent developments. This is seen along two lines: (1) extended scope for the more accurate methods in order to cover larger unit cells and (2) better precision in measurements of intensities.
Zusätzliches Material:
11 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jemt.1060130203
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