Cation Valence States of Transitional Metal Oxides Analyzed by Electron Energy-Loss Spectroscopy

2005 ◽  
pp. 87-110
Author(s):  
Zhong Lin Wang
Keyword(s):  
Energy Loss ◽  
Metal Oxides ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Transitional Metal ◽  
Valence States ◽  
Transitional Metal Oxides ◽  
Electron Energy Loss

Fast Mapping of the Cobalt-Valence State in Ba0.5Sr0.5Co0.8Fe0.2O3-dby Electron Energy Loss Spectroscopy

2013 ◽  
Vol 19 (6) ◽  
pp. 1595-1605 ◽  
Author(s):  
Philipp Müller ◽  
Matthias Meffert ◽  
Heike Störmer ◽  
Dagmar Gerthsen
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Valence State ◽  
Hexagonal Phase ◽  
Fast Method ◽  
White Line ◽  
Valence States ◽  
Electron Energy Loss

AbstractA fast method for determination of the Co-valence state by electron energy loss spectroscopy in a transmission electron microscope is presented. We suggest the distance between the Co-L3and Co-L2white-lines as a reliable property for the determination of Co-valence states between 2+ and 3+. The determination of the Co-L2,3white-line distance can be automated and is therefore well suited for the evaluation of large data sets that are collected for line scans and mappings. Data with a low signal-to-noise due to short acquisition times can be processed by applying principal component analysis. The new technique was applied to study the Co-valence state of Ba0.5Sr0.5Co0.8Fe0.2O3-d(BSCF), which is hampered by the superposition of the Ba-M4,5white-lines on the Co-L2,3white-lines. The Co-valence state of the cubic BSCF phase was determined to be 2.2+ (±0.2) after annealing for 100 h at 650°C, compared to an increased valence state of 2.8+ (±0.2) for the hexagonal phase. These results support models that correlate the instability of the cubic BSCF phase with an increased Co-valence state at temperatures below 840°C.

Inner shell electron-energy loss spectroscopy of some heterocyclic molecules

1986 ◽  
Vol 64 (6) ◽  
pp. 1145-1155 ◽  
Author(s):  
D C Newbury ◽  
I Ishii ◽  
A P Hitchcock
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Small Angle ◽  
Electric Dipole ◽  
Electron Energy Loss Spectroscopy ◽  
Bond Lengths ◽  
Heterocyclic Molecules ◽  
Valence States ◽  
Dipole Scattering ◽  
Electron Energy Loss

The carbon K-shell spectra of gaseous furan, pyrrole, tetrahydrofuran, pyrrolidine, tetrahydropyran, and piperidine have been recorded by electron energy loss spectroscopy (ISEELS) under electric dipole scattering conditions (2.5 keV impact, small angle.) The spectra are dominated by transitions to unoccupied valence states of π and σ symmetry. Features attributed to transitions to π*(CH2) levels are consistently observed below the ionization threshold in the spectra of the saturated species. the positions of continuum features are generally in agreement with a previously documented correlation with bond lengths. Additional weak continuum features are observed in the smaller saturated heterocyclic species which are ascribed to delocalized σ* states.

Sign in / Sign up

Export Citation Format

Share Document