EXTENDED ENERGY LOSS FINE STRUCTURE (EELFS) ABOVE THE CARBON K-EDGE IN CF4STUDIED AT DIFFERENT MOMENTUM TRANSFERS

1987 ◽  
Vol 48 (C9) ◽  
pp. C9-1125-C9-1128 ◽  
Author(s):  
P. LETARDI ◽  
R. CAMILLONI ◽  
G. STEFANI
Keyword(s):  
Fine Structure ◽  
Energy Loss

Some Aspects of Exelfs Analysis in the Electron Microscope

1980 ◽  
Vol 38 ◽  
pp. 118-119
Author(s):  
D. E. Johnson ◽  
S. Csillag
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Energy Loss ◽  
Analytical Electron Microscopy ◽  
Interference Effects ◽  
Interatomic Distances ◽  
X Ray ◽  
Structure Information ◽  
Microanalytical Technique ◽  
Analytical Electron

Recently, the applications area of analytical electron microscopy has been extended to include the study of Extended Energy Loss Fine Structure (EXELFS). Modulations past an ionization edge in the energy loss spectrum (EXELFS), contain atomic fine structure information similar to Extended X-ray Absorbtion Fine Structure (EXAFS). At low momentum transfer the main contribution to these modulations comes from interference effects between the outgoing excited inner shell electron waves and electron waves backscattered from the surrounding atoms. The ability to obtain atomic fine structure information (such as interatomic distances) combined with the spatial resolution of an electron microscope is unique and makes EXELFS an important microanalytical technique.

Analysis of Extended Energy-Loss Fine Structure of Nanometerscale Clusters

1999 ◽  
Vol 5 (S2) ◽  
pp. 708-709
Author(s):  
Y. Ito ◽  
H. Jain ◽  
D.B. Williams
Keyword(s):  
Fine Structure ◽  
Energy Loss ◽  
Atomic Clusters ◽  
Nanometer Scale ◽  
X Ray ◽  
Small Clusters ◽  
Electron Energy Loss ◽  
X Ray Absorption ◽  
Ionization Edge

Small atomic clusters are of great importance for applications such as catalysts whose activity depends on the surface of the cluster. Attempts to determine the atomic short-range order and size of clusters have been made by analyzing the extended X-ray absorption fine structure (EXAFS). However, the analysis was made on an average of many small clusters. Analysis of extended energy-loss fine structure (EXELFS) in an electron energy-loss spectrum (EELS) has developed to the point where in some cases, the quality of the results is comparable to its X-ray analogue, EXAFS. No other technique provides nanometer-scale spatial resolution of the analyzed area for determining the atomic structure. Most EXELFS analysis has been performed on the K-ionization edge of lighter elements. For heavier elements, a more complex ionization edge such as the L-edge has to be used, due to the inefficiency of collecting high quality EEL spectra at higher energy-losses (Z > 18).

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