Modeling EPR Powder Spectra Using Numerical Diagonalization of the Spin Hamiltonian

Morin, Guillaume; Bonnin, D.

doi:10.1006/jmre.1998.1615

Cited by 59 publications

(56 citation statements)

References 48 publications

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“…The a-A1203 spectrum is similar to the room temperature spectra reported by De Biasi and Rodrigues (1983) and Morin and Bonnin (1999). However, weakly allowed transitions at low magnetic field are absent because the recording temperatures differ.…”

Section: Resultssupporting

confidence: 85%

“…The fine-structure parameters of the Fe 3+ site in ~x-A1203 at 120 K were refined following the method of Morin and Bonnin (1999), which is based on a fulldiagonalization of the spin Hamiltonian (B ~ = 0.0572 cm-~; 60 • B4 ~ = -0.0114 cm-J; 60 • B43 = 0.2257 cm -~, where B ~ B ~ and B 3 are the conventional finestructure parameters for the trigonal symmetry of Fe 3+ site in o~-m1203). These parameters differ slightly from those refined at room temperature (Bogle and Syrnmons, 1959;Morin and Bonnin, 1999 Figure 1. X-band EPR spectra normalized against gain and sample weight (see text) of four kaolinite samples (A1, KGa-1, KGa-2, and DCV) and standard (0.157<).…”

Section: Resultsmentioning

confidence: 99%

“…The present study determines a quantitative approach to measure dilute structural Fe 3+ by combining calculation of X-band EPR spectra (Balan et aL, 1999;Morin and Bonnin, 1999) with data from an Fe3+-doped c~-A1203 standard.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative Measurement of Paramagnetic Fe³⁺ in Kaolinite

Balan

2000

Clays and clay miner.

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Abstract--A method is proposed to measure the absolute concentration of paramagnetic Fe 3+ ions in kaolinite from various geochemical environments using powder X-band electron paramagnetic resonance (EPR) data. An Fe3+-doped corundum sample is used as a concentration standard. The Fe 3+ signal is calibrated by calculating the powder EPR spectra of Fe 3+ ions in corundum and low-defect kaolinite. The paramagnetic Fe 3+ concentration in other samples is obtained by an extrapolation procedure. This study provides a direct assessment of the iron distribution between isolated structural Fe 3+ ions and other iron species, such as Fe 3+ concentrated phases and Fe 2+ ions. The concentration of isolated structural Fe 3+ ranges between 200-3000 ppm and represents less than half of the total iron within kaolinite crystals.

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Section: Resultssupporting

confidence: 85%

Section: Resultsmentioning

confidence: 99%

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Quantitative Measurement of Paramagnetic Fe³⁺ in Kaolinite

Balan

2000

Clays and clay miner.

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“…To assure precision ZFSFIT [2] uses bisection method (searching x-intercept of the function f (x) = ∆ ij (x) − ω) for all pairs of eigenstates separates. It is why this technique is slower [1].…”

Section: Model -Used Methodsmentioning

confidence: 99%

“…There are some softwares prepared for such data analyzes (XSophe [1], ZFSFIT [2], EasySpin [3]) but they either use noneffective algorithms or do not guarantee demanded precision.…”

Section: Introductionmentioning

confidence: 99%

EPR Spectra of Multispin Systems. Application to Poly-m-p-Aniline

et al. 2011

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In this communication we present NiceMagnetic, software for simulations and analysis of EPR spectrum and SQUID measurements. Systems of arbitrary number N of spin-only magnetic moments (S = 0 and L = 0) were considered within the lines of the Heisenberg and Zeeman Hamiltonians. Effective algorithms used for the computations are discussed. This includes modified secant method adapted to calculate resonance fields with demanded precision. Finally, application of NiceMagnetic to experimental SQUID magnetization and EPR spectra of poly-m-p-aniline, one of recently synthesized high spin polymers containing unpaired electrons will be presented. As a result, exchange integral between electron and nitrogen nuclei spins (ligand hyperfine interaction) J = 6.3 × 10 −4 cm −1 was estimated.

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