Integral low-energy electron diffraction patterns from surface of crystals. (USSR)

Vacuum ◽  
1977 ◽  
Vol 27 (1) ◽  
pp. 46
Keyword(s):  
Electron Diffraction ◽  
Low Energy ◽  
Energy Electron ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Diffraction Patterns ◽  
Surface Of Crystals

LOW-ENERGY ELECTRON HOLOGRAMS: PROPERTIES AND METHOD OF INVERSION

1997 ◽  
Vol 04 (03) ◽  
pp. 459-467 ◽  
Author(s):  
S. Y. TONG ◽  
T. P. CHU ◽  
HUASHENG WU ◽  
H. HUANG
Keyword(s):  
Electron Diffraction ◽  
Integral Transformation ◽  
Low Energy ◽  
Energy Electron ◽  
Wave Number ◽  
Large Wave ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Diffraction Patterns ◽  
Large Wave Number

We examine the differences between low-energy electron-diffraction patterns (holograms) and optical holograms. We show that electron-diffraction patterns in solids are not analogous to optical holograms because of strong dynamical factors. We also show that low-energy electron holograms can be inverted by a large-wave-number small-angle integral transformation. The grid sizes in wave number and angular spaces used in the transformation are derived.

Studies on surfaces of Zr(0001) that contain oxygen and show (2 × 2)-type low-energy electron diffraction patterns

1987 ◽  
Vol 65 (5) ◽  
pp. 464-467 ◽  
Author(s):  
P. C. Wong ◽  
K. A. R. Mitchell
Keyword(s):  
Electron Diffraction ◽  
Room Temperature ◽  
Low Energy ◽  
Energy Electron ◽  
Leed Pattern ◽  
Low Energy Electron Diffraction ◽  
Adsorption Sites ◽  
Low Energy Electron ◽  
Low Exposure ◽  
Diffraction Patterns

Oxygen chemisorption on the Zr(0001) surface has been studied in the low-exposure regime with Auger electron spectroscopy and measurements of the width of a half-order low-energy electron diffraction (LEED) beam. The new observations and conclusions are as follows. (i) The diffusion of O atoms to the bulk effectively starts at around 236 °C. (ii) Oxygen adsorbs in a disordered state at room temperature and orders sufficiently to show a (2 × 2)-type LEED pattern on heating to 220 °C. (iii) With increasing O exposure, 1/4, 1/2, and 3/4 of the available adsorption sites can be systematically filled, while showing the apparent (2 × 2)-LEED pattern, prior to the establishment of an ordered (1 × 1)-O surface. (iv) The process in (iii) can be reversed by starting with the (1 × 1)-O surface and heating above 236 °C.

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