Electron diffraction low-energy

Low-Energy Electron Diffraction, LEED 252 Reflection High-Energy Electron Diffraction, RHEED 264 

Diffraction Low energy electron diffraction LEED Electron Electron 

LEED Low-energy electron diffraction [62, 75, 105] Elastic backscattering of electrons (10-200 eV) Surface structure 

The diffraction of low-energy electrons (and any other particles, like x-rays and neutrons) is governed by the translational syimnetry of the surface, i.e. the surface lattice. In particular, the directions of emergence of the diffracted beams are detemiined by conservation of the linear momentum parallel to the surface, bk,. Here k 

Pendry J B 1974 Low-energy Electron Diffraction (London Aoademio) 

Another mode of electron diffraction, low energy electron diffraction or FEED [13], uses incident beams of electrons with energies below about 100 eV, with corresponding wavelengths of the order of 1 A. Because of the very strong interactions between the incident electrons and tlie atoms in tlie crystal, there is very little penetration of the electron waves into the crystal, so that the diffraction pattern is detemiined entirely by the 

G. Ertl and J. Kiippers. Low-Energy Electrons and Surface Chemistry. Verlag Chemie, Weinheim, 1974, Chps. 9 and 10. An introductory treatment of diffraction. 

Rous P J 1993 A global approach to the search problem in surface crystallography by low-energy electron diffraction Surf. Sc 296 358-73 

We will, in the latter part of this discussion, focus only on those few methods that have been the most productive, with low-energy electron diffraction (FEED) receiving the most attention. Indeed, LEED has been the most successfiil surface stmctiiral method in two quite distinct ways. First, LEED has become an almost universal characterization 

Surface-sensitive diffraction is, for the most part, restricted to analysis of surfaces of single crystals and overlayers and films on such surfaces. If a polycrystalline sample is illuminated using a beam of low-energy electrons, each crystallite surfiice exposed will create its own diffraction pattern, all of which will be superimposed on the fluorescent screen detector. If more than a few orientations are illuminated by the beam, the pattern becomes too complicated to analyze. Flowever, if the size of the 

This chapter contains articles on six techniques that provide structural information on surfaces, interfeces, and thin films. They use X rays (X-ray diffraction, XRD, and Extended X-ray Absorption Fine-Structure, EXAFS), electrons (Low-Energy Electron Diffraction, LEED, and Reflection High-Energy Electron Diffraction, RHEED), or X rays in and electrons out (Surfece Extended X-ray Absorption Fine Structure, SEXAFS, and X-ray Photoelectron Diffraction, XPD). In their usual form, XRD and EXAFS are bulk methods, since X rays probe many microns deep, whereas the other techniques are surfece sensitive. There are, however, ways to make XRD and EXAFS much more surfece sensitive. For EXAFS this converts the technique into SEXAFS, which can have submonolayer sensitivity. 

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