Landolt-Börnstein - Group III Condensed Matter

6.1.1.4.1.6 Precision and reliability

Abstract

This chapter discusses precision and reliability of low-energy electron diffraction (LEED) technique. From the early years of the LEED technique, a large amount of work was devoted to the assessment of data reproducibility and to the analysis of accuracy in surface determinations. The accuracy of structural determinations also owes something to the evaluation of instrument response function, i.e. to the effect introduced by angular divergence and energy spreading of the incident beam on the coherence length of the electrons, and on the response of the intensity measurement apparatus. The instrument response function seems more important for the application of LEED to the study of defects than for the structural parameters derived from the intensity analysis, because the overall effect, both instrumental and from disorder, results in a scale factor of the I/V curves, without any important changes in their shape. However, there are different causes of errors when comparing theoretical and experimental curves, some of these being errors in the determination of the angles of incidence and azimuth, or due to the residual magnetic field. To minimize their effect, an appropriate average of the intensity of beams which are symmetrically equivalent can be used. It is difficult to make an overall evaluation of the degree of precision that can be reached, because of the lack of different methods which are absolutely sure and of well known structural determinations.

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Title
6.1.1.4.1.6 Precision and reliability
Book Title
Interaction of Charged Particles and Atoms with Surfaces
In
6.1.1.4.1 LEED
Book DOI
10.1007/b87125
Chapter DOI
10.1007/10086066_17
Part of
Landolt-Börnstein - Group III Condensed Matter
Volume
24C
Editors
  • G. Chiarotti
  • Authors
  • E. Zanazzi
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