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EXAFS measurements with femtometer accuracy: isotopic effect in the first, second, and third coordination shells of germanium

F Rocca;
2009
2009
Istituto di fotonica e nanotecnologie - IFN
XAFS14 - XIX “International Conference on X-ray Absorption fine Structure” , 26-31 July 2009
No
Camerino, MC (Italia)
Abstract:Recently we have shown that isotopic effect in polycrystalline germanium can be successfully probed by the extended x-ray absorption fine structure (EXAFS) technique with femtometer accuracy (see highlight ESRF 2008). The analysis of the first coordination shell in two powders 70Ge and 76Ge has evidenced the effect of isotopic mass difference on the amplitude of relative atomic vibrations, reflected in the temperature dependence of the difference of Debye-Waller factors, and on the difference of nearest-neighbor average interatomic distances. In this work we extend our analysis of the available Ge K-edge EXAFS data[1] to the second and third coordination shells, where a contribution of multiple-scattering (MS) effects into EXAFS signal is expected. The Debye-Waller (DW) factors have been obtained for two isotopes of 70Ge and 76Ge using the best fit procedure of the EXAFS signals within the MS approximation in the temperature range from 20 to 300K. The determined temperature dependencies of the DW factors have been used to calculate the characteristic frequencies within the Einstein model. The obtained values of the characteristic frequencies are in good agreement with those expected from the variation of the isotopic mass.
1
none
J. Purans; J. Timoshenko; A. Kuzmin; G. Dalba; P. Fornasini; R. Grisenti; N.D. Afify; F. Rocca; S. De Panfilis; V.I. Ozhogin; S.I. Tiutiunnikov...espandi
273
info:eu-repo/semantics/conferenceObject
04 Contributo in convegno::04.01 Contributo in Atti di convegno
04.01 Contributo in Atti di convegno
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/151882
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