Publication
Title
Reanalysis and identification of an $Rh^{2+}$ dimer center in NaCl by combined application of 9.5 and 95 GHz EPR
Author
Abstract
 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.
Language
English
Source (journal)
Journal of the Chemical Society : Faraday transactions: physical chemistry and chemical physics / Bunsengesellschaft für Physikalische Chemie. - London, 1990 - 1998
Source (book)
31st International Meeting of the ESR Group of the Royal-Society-of-Chemistry, 1998, UNIV MANCHESTER, MANCHESTER, ENGLAND
Publication
London : Royal Society of Chemistry , 1998
ISSN
0956-5000 [print]
1364-5455 [online]
Volume/pages
94 :19 (1998) , p. 3003-3007
ISI
000076287900023
Full text (Publisher's DOI)
Full text (open access)
UAntwerpen
 Faculty/Department Research group Publication type Subject Affiliation Publications with a UAntwerp address