A Rigorous Evaluation of Spin-Hamiltonian Parameters and Linewidth from a Polycrystalline EPR Spectrum

1999 ◽  
Vol 140 (1) ◽  
pp. 179-188 ◽  
Author(s):  
Sushil K. Misra
Keyword(s):  
Spin Hamiltonian ◽  
Epr Spectrum ◽  
Rigorous Evaluation ◽  
Hamiltonian Parameters

EPR spectra of a new radiation-induced paramagnetic centre in kaolins

Clay Minerals ◽  
2016 ◽  
Vol 51 (5) ◽  
pp. 707-714 ◽  
Author(s):  
Bernard A. Goodman ◽  
Niramon Worasith ◽  
Wen Deng
Keyword(s):  
Radiation Dose ◽  
Spin Hamiltonian ◽  
Paramagnetic Centre ◽  
Epr Spectrum ◽  
Γ Radiation ◽  
Rhombic Symmetry ◽  
Radiation Induced ◽  
Epr Signal ◽  
A Minor ◽  
Hamiltonian Parameters

AbstractThe EPR spectrum of a previously unreported paramagnetic centre formed in kaolin minerals by exposure to γ radiation is described. This centre, which is referred to here as the ‘C-centre’, was seen initially during an investigation of the radiation dose response of the EPR signal in the natural Lampang kaolin from northern Thailand, and its EPR properties are now presented for a purified sample from this material. They suggest a paramagnetic centre with rhombic symmetry based on O− associated with a single 27Al atom. Computer simulations suggest spin Hamiltonian parameters of g1 = 1.976, g3 = 2.0417 and A(27Al) = 2.10 mT, with g2 ≈ 2.01. This C-centre was also seen as a minor radiationinduced component in both crude and purified Ranong kaolin samples, along with a stronger signal from the B-centre radical. It seems to be associated with the kaolinite component, but was lost on annealing to 300°C after which only the signal from the A-centre was visible.

EPR Studies of Mn2+-Doped Diammonium Hexaaqua Magnesium(II) Sulfate

2006 ◽  
Vol 61 (12) ◽  
pp. 683-687 ◽  
Author(s):  
Ram Kripal ◽  
Ashutosh Kumar Shukla
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Fine Structure ◽  
Single Crystals ◽  
Room Temperature ◽  
Spin Hamiltonian ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
X Band ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

Electron paramagnetic resonance (EPR) studies of Mn2+ impurity in single crystals of diammonium hexaaqua magnesium(II) sulfate have been carried out at 9.3 GHz (X-band) at room temperature. The EPR spectra exhibit a group of five fine structure transitions. The spin-Hamiltonian parameters were determined. Mn2+ enters the lattice interstitially. The EPR spectrum of a powder sample supports the data obtained by single crystal studies. - PACS number: 76.30

EPR Spectra of Some Cu2+-Doped Metal Carbonates and Disorder Phase Transition in K3H(CO3)2

2009 ◽  
Vol 64 (1-2) ◽  
pp. 123-126 ◽  
Author(s):  
Dilek Demir ◽  
Fevzi Köksal ◽  
Canan Kazak ◽  
Rahmi Köseoğlu
Keyword(s):  
Phase Transition ◽  
Low Temperatures ◽  
The Other ◽  
Spin Hamiltonian ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Disorder Phase Transition ◽  
Metal Carbonates ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

Cu2+-doped K3H(CO3)2, Rb2CO3, and Rb2KH(CO3)2 single crystals were investigated by electron paramagnetic resonance (EPR) spectroscopy. The EPR spectrum of K3H(CO3)2 indicates two different sites for Cu2+ at room and at low temperatures. But the signals for the two sites overlap at 318 K which is attributed to a disorder phase transition. Each of the other compounds exhibits one site. The Cu2+ ion seems to substitute the K+ and Rb+ ions and the charge compensations are fulfilled by the proton vacancies in K3H(CO3)2, and another K+ and Rb+ in the other compounds. The spin Hamiltonian parameters g and A for each compound are determined and discussed.

ELECTRON PARAMAGNETIC RESONANCE OF MANGANESE IN CESIUM AND AMMONIUM CHLORIDES

1967 ◽  
Vol 45 (10) ◽  
pp. 3381-3386 ◽  
Author(s):  
A. Forman ◽  
J. A. Van Wyk
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Fine Structure ◽  
Line Width ◽  
Structure Parameter ◽  
Manganese Ions ◽  
Spin Hamiltonian ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

The spin-Hamiltonian parameters describing the EPR spectrum of Mn2+ in CsCl crystals grown from solutilon have been determined. The line-width data are in agreement with the manganese ions being incorporated interstitially rather than substitutionally for Cs+ ions. From the work on Mn2+ in NH4Cl we infer that the fine structure parameter, D2, is negative.

scholarly journals Статический и динамический вклады в расщепление основного состояния Eu-=SUP=-2+-=/SUP=- в SrMoO-=SUB=-4-=/SUB=-

2019 ◽  
Vol 61 (5) ◽  
pp. 905
Author(s):  
А.Д. Горлов
Keyword(s):  
Thermal Expansion ◽  
Single Crystal ◽  
Impurity Center ◽  
Spin Hamiltonian ◽  
Lattice Thermal Expansion ◽  
Epr Spectrum ◽  
Small Temperature ◽  
Temperature Changes ◽  
Hamiltonian Parameters ◽  
Static Lattice

AbstractThe EPR spectrum of an Eu^2+ impurity center in a SrMoO_4 single crystal in the temperature range T = 1.8, 111–300 K has been studied, and the temperature changes in the spin Hamiltonian parameters describing the EPR spectrum of odd europium isotopes have been determined. It is shown that small temperature changes in the diagonal parameters of the spin Hamiltonian (for odd Eu^2+ isotopes) $$b_{2}^{0}$$ ( T ) = b _2( F ) + b _2( L ) and $$P_{2}^{0}$$ ( T ) = P _2( F ) + P _2( L ) are explained by the compensation of spin–phonon contributions b _2( F ) and P _2( F ) by the contributions of the lattice thermal expansion b _2( L ) and P _2( L ). The quantities b _2( L ) and P _2( L ) that are dependent on the static lattice parameters at a given temperature, are estimated in terms of the superposition Newman model. Then, the spin–phonon b _2( F ) and P _2( F ) contributions determined by the lattice ion vibrations are separated. An analysis shows that $$b_{2}^{0}$$ ( F ) and $$P_{2}^{0}$$ ( F ) > 0, b _2( L ) and P _2( L ) < 0, and the temperature behavior of the spin–phonon contribution is well described by G. Pfister’s model of local vibrations.

scholarly journals Identification of the Negative Carbon Vacancy at Quasi-Cubic Site in 4H-SiC by EPR and Theoretical Calculations

2014 ◽  
Vol 778-780 ◽  
pp. 285-288
Author(s):  
Xuan Thang Trinh ◽  
Krisztián Szász ◽  
Tamas Hornos ◽  
Koutarou Kawahara ◽  
Jun Suda ◽  
...  
Keyword(s):  
Room Temperature ◽  
Defect Formation ◽  
Theoretical Calculations ◽  
Low Energy ◽  
Spin Hamiltonian ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Carbon Vacancy ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

In freestandingn-type 4H-SiC epilayers irradiated with low-energy (250 keV) electrons at room temperature, the electron paramagnetic resonance (EPR) spectrum of the negative carbon vacancy at the hexagonal site, VC- (h), and a new signal were observed. From the similarity in defect formation and the spin-Hamiltonian parameters of the two defects, the new center is suggested to be the negative C vacancy at the quasi-cubic site, VC- (k). The identification is further supported by hyperfine calculations.

scholarly journals Парамагнитные центры хрома в кристаллах Y-=SUB=-2-=/SUB=-SiO-=SUB=-5-=/SUB=- и Sc-=SUB=-2-=/SUB=-SiO-=SUB=-5-=/SUB=-

2018 ◽  
Vol 60 (10) ◽  
pp. 1995
Author(s):  
В.А. Важенин ◽  
А.П. Потапов ◽  
Г.С. Шакуров ◽  
А.В. Фокин ◽  
М.Ю. Артёмов ◽  
...  
Keyword(s):  
Single Crystals ◽  
Spin Hamiltonian ◽  
Epr Spectrum ◽  
Chromium Ions ◽  
Hamiltonian Parameters

AbstractThe EPR spectrum of yttrium and scandium silicate single crystals doped with chromium has been studied at various frequencies. Y_2SiO_5 has one triclinic Cr^3+ center, while the Sc_2SiO_5 crystals demonstrate two nonequivalent centers. The spin Hamiltonian parameters of these centers have been determined. These centers are found to be tricharged chromium ions localized in the yttrium and scandium positions.

ESR STUDY OF SPIN-HAMILTONIAN PARAMETERS AND CRYSTAL FIELD ENERGY LEVELS FOR THE LOW C3 SYMMETRY Fe3+ CENTER IN GREEN SAPPHIRE CRYSTALS AND POWDER

2007 ◽  
Vol 21 (04) ◽  
pp. 225-236 ◽  
Author(s):  
P. LIMSUWAN ◽  
N. UDOMKAN ◽  
P. WINOTAI
Keyword(s):  
Rotation Angle ◽  
Energy Levels ◽  
Heat Treating ◽  
Esr Spectra ◽  
Field Energy ◽  
Hamiltonian Matrix ◽  
Magnetic Field Direction ◽  
Spin Hamiltonian ◽  
Corundum Structure ◽  
Hamiltonian Parameters

In this report, Fe 3+ impurity ions present in green sapphire ( Al 2 O 3) were studied experimentally, by heating a light green sapphire in flowing oxygen atmosphere for 12 h from 1200, 1300, 1400, 1500 and 1600°C, respectively. Electron spin resonance (ESR) spectra in X-band (~9.45 GHz ) were recorded by mounting the crystal with the c-axis perpendicular (θ = 90°) to the magnetic field direction. The spectra were recorded and simulated by a numerical diagonalization of spin Hamiltonian matrix in the range from 0 to 180 degrees for every 15 degrees of rotation angle (φ). In our case, only the last two sets of peaks strongly depend on the rotation angle (φ), and each exhibits C 3 symmetry due to two magnetically inequivalent Fe 3+ sites in the corundum structure. For polycrystalline ESR spectra, seven main Fe 3+ ESR absorption peaks occur at the resonance magnetic fields of 100.20, 310.24, 486.80, 525.00, 550.60, 761.00 and 777.00 mT respectively. Specifically, ESR signals show that the number of paramagnetic Fe 3+ ions increase roughly linearly with the heat treating temperature, having the [Formula: see text] ratio ~1.41 at 1600°C.

EPR Spectroscopy Elucidates the Electronic Structure of [FeV(O)(TAML)] Complexes

2021 ◽  
Author(s):  
Yujeong Kim ◽  
Jin Kim ◽  
Linh. K. Nguyen ◽  
Yong-Min Lee ◽  
Wonwoo Nam ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Epr Spectroscopy ◽  
Macrocyclic Ligands ◽  
Spin Hamiltonian ◽  
Pulse Epr ◽  
Hamiltonian Parameters

Multifrequency, multitechnique pulse EPR spectroscopy was employed to unravel the spin Hamiltonian parameters of 17O in the [FeV=O] moiety with two different tetraamido macrocyclic ligands (TAMLs), [FeV(O)(TAML-1)]– (1, H4(TAML-1) =...

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