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Title
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Reanalysis and identification of an dimer center in NaCl by combined application of 9.5 and 95 GHz EPR
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Author
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Abstract
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| A combined 9.5 (X-band) and 95 GHz (W-band) EPR study of an Rh2+ dimer center in Bridgman-grown rhodium-doped NaCl is presented. A close-to-tetragonal symmetry, similar to that of the monomer centers, with dominant symmetry axis along [001], the z-axis, is observed for this defect. The dimer and monomer spectra, which strongly overlap in the X-band spectra, could be well separated in the W-band measurements due to the higher g-resolution at higher magnetic fields. The anisotropy in the perpendicular plane, with [110] symmetry directions, is shown, from the combined X-and W-band spectra, to derive predominantly from a held-independent contribution, i.e. an orthorhombic spin-spin interaction, S-1.D.S-2 (S-1 = S-2 = 1/2), while the g matrices are near to axial, as in the case of the RhCl64-.2Vac monomer center (Vac = cation vacancy). This dimer center is shown to consist of a square arrangement of two substitutional Rh2+ ions and two next-nearest neighbor cation vacancies in an {001}-plane, with the Rh2+ ions on opposite corners at a distance of ca. 7.6 Angstrom, as estimated from the magnitude of the dipolar interaction. This work illustrates the ability of combined EPR experiments at widely different frequencies to discriminate field-independent from field-dependent terms in the spin-Hamiltonian. |
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Language
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English
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Source (journal)
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Journal of the Chemical Society : Faraday transactions: physical chemistry and chemical physics / Bunsengesellschaft für Physikalische Chemie. - London, 1990 - 1998
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Source (book)
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31st International Meeting of the ESR Group of the Royal-Society-of-Chemistry, 1998, UNIV MANCHESTER, MANCHESTER, ENGLAND
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Publication
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London
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Royal Society of Chemistry
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1998
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ISSN
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0956-5000
[print]
1364-5455
[online]
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DOI
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10.1039/A803244K
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Volume/pages
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94
:19
(1998)
, p. 3003-3007
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ISI
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000076287900023
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Full text (Publisher's DOI)
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Full text (open access)
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