Measurements of iron concentration in kaolinites considering disorder broadening of EPR lines
| Autor: | S. Jemai, J. M. Gaite, Fabrice Muller |
|---|---|
| Přispěvatelé: | Institut des Sciences de la Terre d'Orléans (ISTO), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Matériaux, Faculté des Sciences de Bizerte [Université de Carthage], Université de Carthage - University of Carthage-Université de Carthage - University of Carthage |
| Jazyk: | angličtina |
| Rok vydání: | 2003 |
| Předmět: |
010302 applied physics
Range (particle radiation) Chemistry [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] Analytical chemistry Fe 3+ Observable [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] 01 natural sciences Spectral line Intensity (physics) law.invention Geochemistry and Petrology law Kaolinite 0103 physical sciences General Materials Science EPR 010306 general physics Electron paramagnetic resonance Order of magnitude Line (formation) |
| Zdroj: | Physics and Chemistry of Minerals Physics and Chemistry of Minerals, Springer Verlag, 2003, 30, pp.(6) 366-372. ⟨10.1007/s00269-003-0325-3⟩ |
| ISSN: | 0342-1791 1432-2021 |
| DOI: | 10.1007/s00269-003-0325-3⟩ |
| Popis: | Only one part of the EPR lines of a kaolinite spectrum of structural Fe 3+ is clearly observable because of the overlapping of other lines with other spectra. For this reason, to determine the structural Fe 3+ concentration we used the line near g=9, although it is not intense. A standard is needed: powders of ZnS containing given concentrations of Mn 2+ (isoelectronic to Fe 3+) were used for this purpose. Using the simulations of the EPR spectra, the concentration (number of Fe 3+ per Al 3+) is determined; it is in the range 10 -5 to 10 -4 for our samples. Considering that the crystal-field disorder around Fe 3+ is responsible for line broadening, we looked for a possible effect of the broadening on the intensity of the EPR spectra. This effect is taken as a distribution of the parameter ?= B 2 2/ B 2 0. The influence of the parameter ? and its statistical distribution on the position, shape, width and intensity of the EPR line has been calculated using simulation procedures. The correction due to the disorder on the calculated concentration is of the same order of magnitude as the precision measurement. This method can be applied for other kaolinites by comparing the area of their g=9 lines with known ones. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink