Diffraction of electrons by metal crystals and by mica

The object of the research was to study the spot patterns produced when an electron beam of homogeneous velocity ~ 30 kV is transmitted through a thin crystalline film. Such spot patterns were first reported by Kikuchi, and their importance lies in the fact that they are regarded as being due to single crystals of matter; the study of the diffraction of electrons by single crystals must necessarily precede the exact explanation of the Debye-Scherrer patterns obtained when random aggregates are employed. The results described below have a direct bearing on the latter problem. Electron diffraction spot patterns due to the transmission of 30 kV electrons have been studied by Thomson, Kirchner, Trillat and Hirsch, Lassen. But the interpretations of these pseudo-two-dimensional effects has remained uncertain.

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EXTRAX: anImageJplug-in for electron diffraction intensity extraction

Journal of Applied Crystallography ◽

10.1107/s0021889809049267 ◽

2009 ◽

Vol 43 (1) ◽

pp. 191-195 ◽

Cited By ~ 2

Author(s):

V. Dorcet ◽

X. Larose ◽

C. Fermin ◽

M. Bissey ◽

P. Boullay

Keyword(s):

Image Processing ◽

Electron Diffraction ◽

Public Domain ◽

High Order ◽

Diffraction Spot ◽

Two Dimensional ◽

Diffraction Intensity ◽

Dimensional Lattice ◽

Peak Location ◽

Modulation Vector

A plug-in (EXTRAX) has been developed forImageJ– a public domain Java-based program widely used for image processing and analysis in microscopy. This plug-in allows the extraction and measurement of intensities from electron diffraction spot patterns with a semi-automatic peak location based on a two-dimensional lattice given by the user. It is also possible to take into account supplementary spots originating from high-order Laue zones and/or the existence of a modulation vector.

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Montmorillonite: Electron Diffraction from Two-Dimensional Single Crystals

Science ◽

10.1126/science.176.4037.908 ◽

1972 ◽

Vol 176 (4037) ◽

pp. 908-909 ◽

Cited By ~ 5

Author(s):

H. E. Roberson ◽

K. M. Towe

Keyword(s):

Electron Diffraction ◽

Single Crystals ◽

Two Dimensional

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The decomposition of magnesium hydroxide in an electron microscope

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1958.0188 ◽

1958 ◽

Vol 247 (1250) ◽

pp. 346-352 ◽

Cited By ~ 72

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

Electron Diffraction ◽

Single Crystals ◽

Magnesium Oxide ◽

Magnesium Hydroxide ◽

Basal Plane ◽

Morphological Changes ◽

Water Molecules ◽

Two Stages

The beam of an electron microscope has been used to dehydrate single crystals of magnesium hydroxide to magnesium oxide. Electron diffraction photographs and electron micrographs were taken at various stages to follow the crystallographic and morphological changes which accompany decomposition. The decomposition may be considered to occur in two stages. First, there is a small shrinkage in the basal plane, and the resulting strain causes a maze of cracks in the crystal. This change is followed by a collapse of the planes down the original [0001] of magnesium hydroxide. The collapse is controlled by the migration of water molecules from between the planes to a surface where they can escape. The product is a highly oriented aggregate of micro-crystallites of magnesium oxide. More intense irradiation in the electron beam occasionally causes bulk movement of the solid.

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MEASUREMENTS OF AUGER ELECTRON DIFFRACTION USING A 180° DEFLECTION TOROIDAL ANALYZER

Surface Review and Letters ◽

10.1142/s0218625x99000536 ◽

1999 ◽

Vol 06 (05) ◽

pp. 585-590 ◽

Cited By ~ 7

Author(s):

SUSUMU SHIRAKI ◽

HIDESHI ISHII ◽

YOSHIMASA NIHEI ◽

MASANORI OWARI

Keyword(s):

Electron Beam ◽

Electron Diffraction ◽

Multiple Scattering ◽

Auger Electron ◽

Theoretical Data ◽

Two Dimensional ◽

Electron Spectrometer ◽

Simultaneous Registration ◽

Wide Range ◽

Good For

A 180° deflection toroidal analyzer is a novel electron spectrometer, which allows the simultaneous registration of the wide range of polar angles in a given azimuth of the sample. Therefore, measurements of photo- and Auger electron intensities over π steradians can be performed rapidly by azimuthal rotation of the sample. Using this analyzer, two-dimensional patterns of electron-beam-excited O KVV and Mg KVV Auger electron diffraction (AED) from a MgO(001) surface were measured in short acquisition times. The AED patterns obtained were compared with theoretical ones calculated by the multiple-scattering scheme. The agreement between experimental and theoretical data was good for both O KVV and Mg KVV transitions.

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The crystalline structure of two-dimensional cyanine dye single crystals as revealed by electron diffraction

Thin Solid Films ◽

10.1016/0040-6090(88)90068-5 ◽

1988 ◽

Vol 160 (1-2) ◽

pp. 251-255 ◽

Cited By ~ 33

Author(s):

Claus Duschl ◽

Wolfgang Frey ◽

Wolfgang Knoll

Keyword(s):

Electron Diffraction ◽

Single Crystals ◽

Crystalline Structure ◽

Cyanine Dye ◽

Two Dimensional

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Herringbone structure in two‐dimensional single crystals of cyanine dyes. I. Detailed structure analysis using electron diffraction

The Journal of Chemical Physics ◽

10.1063/1.470114 ◽

1995 ◽

Vol 103 (2) ◽

pp. 818-825 ◽

Cited By ~ 15

Author(s):

S. Kirstein ◽

R. Steitz ◽

R. Garbella ◽

H. Möhwald

Keyword(s):

Electron Diffraction ◽

Single Crystals ◽

Structure Analysis ◽

Cyanine Dyes ◽

Two Dimensional ◽

Detailed Structure ◽

Herringbone Structure

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Convergent Beam Electron Diffraction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070072 ◽

1978 ◽

Vol 36 (3) ◽

pp. 304-315

Author(s):

G. Lehmpfuhl

Keyword(s):

Electron Diffraction ◽

Diffraction Pattern ◽

Crystal Surface ◽

Diffraction Spot ◽

Crystal Thickness ◽

Large Area ◽

Electron Microscopic ◽

Additional Information ◽

Microscopic Investigations

Introduction In electron microscopic investigations of crystalline specimens the direct observation of the electron diffraction pattern gives additional information about the specimen. The quality of this information depends on the quality of the crystals or the crystal area contributing to the diffraction pattern. By selected area diffraction in a conventional electron microscope, specimen areas as small as 1 µ in diameter can be investigated. It is well known that crystal areas of that size which must be thin enough (in the order of 1000 Å) for electron microscopic investigations are normally somewhat distorted by bending, or they are not homogeneous. Furthermore, the crystal surface is not well defined over such a large area. These are facts which cause reduction of information in the diffraction pattern. The intensity of a diffraction spot, for example, depends on the crystal thickness. If the thickness is not uniform over the investigated area, one observes an averaged intensity, so that the intensity distribution in the diffraction pattern cannot be used for an analysis unless additional information is available.

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Quanitative aspects of electron diffraction using electron holography

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100139457 ◽

1995 ◽

Vol 53 ◽

pp. 616-617

Author(s):

E. Völkl ◽

L.F. Allard ◽

B. Frost ◽

T.A. Nolan

Keyword(s):

Electron Beam ◽

Electron Diffraction ◽

Software Package ◽

Spatial Coherence ◽

Electron Holography ◽

Image Intensity ◽

Interference Fringes ◽

Complex Image ◽

The Difference ◽

Recorded Image

Off-axis electron holography has the well known ability to preserve the complex image wave within the final, recorded image. This final image described by I(x,y) = I(r) contains contributions from the image intensity of the elastically scattered electrons IeI (r) = |A(r) exp (iΦ(r)) |, the contributions from the inelastically scattered electrons IineI (r), and the complex image wave Ψ = A(r) exp(iΦ(r)) as:(1) I(r) = IeI (r) + Iinel (r) + μ A(r) cos(2π Δk r + Φ(r))where the constant μ describes the contrast of the interference fringes which are related to the spatial coherence of the electron beam, and Φk is the resulting vector of the difference of the wavefront vectors of the two overlaping beams. Using a software package like HoloWorks, the complex image wave Ψ can be extracted.

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