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Showing 1 to 20 of 27 for “"spin Hamiltonian"”.
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Mössbauer and EPR studies of iron-containing proteins
… observed spectra can be explained in terms of a spin Hamiltonian, which describes the ground electronic spin multiplet and the electron-nuclear interactions. In general, spin-phonon coupling must be taken into account explicitly, and in one case spin-spin interaction of the iron with a radical …
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An X- and Q-band electron paramagnetic resonance study of Mn2+ in a single crystal of NH4Cl0.9I0.1 in the temperature range 77-295 K
… of this crystal is described by a set of spin-Hamiltonian parameters, whose parameters are determined by fitting the various resonance line positions obtained for several angular orientations of the magnetic field relative to the crystal axes. A set of initial parameters is then determined …
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A single-crystal EPR study of radiation-induced defects in selected silicates
… triatomic molecules and is widely used as spin labels in biophysical and biomedical research, in fluorapophyllite has been observed and characterized by single-crystal EPR spectra. Fourier-transform infrared (FTIR) spectrum supports electron-microprobe analyses that fluorapophyllite on the …
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Studies of Nuclear Quadrupole Effects in Transition Metal Complexes by Electron Paramagnetic Resonance
… single crystals and as powders, the following spin-Hamiltonian is deduced for ('63)Cu: (')H = (beta) B(.)g(.)S(' )+(' )hI(.)A(.)S - g(,n) (beta)(,n) B(.)I(' )+(' )QD(I(,z)('2)-5/4) + QE(I(,x)('2)-I(,y)('2)).
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Mossbauer studies of spin coupled binuclear iron centers in proteins
… range have been performed with the intrinsic spin Hamiltonian $\rm {\cal H} = J{\bf S}\sb1\cdot{\bf S}\sb2 + \Sigma\sbsp{i=1}{2}\{{\bf S}\sb{i}\cdot\tilde D\sb{i}\cdot{\bf S}\sb{i} + \beta{\bf S}\sb{i}\cdot\tilde g\sb{i}\cdot{\bf H} + {\bf S}\sb{i}\cdot\tilde a\sb{i}\ \cdot\ {\bf I}\sb{i} + …
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Electron paramagnetic resonance spectroscopic study of two gadolinium centres at calcium sites in synthetic fluorapatite
… 'a') caused by the Gd even isotopes (electron spin: S = 7/2; nuclear spin: I = 0), and suggested the possible presence of a second partly-resolved type of Gd³⁺ centre (the centre 'b') also caused by the Gd even isotopes. The latter was thoroughly disclosed in the W-band spectra. The …
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Multifrequency Electron Paramagnetic Resonance Spectroscopy of Group Viib Carbonyl Radicals
… metal hyperfine, and phosphorus super-hyperfine spin Hamiltonian parameters are reported and compared to values reported for (.)Mn(CO)(,5).
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The effect of uniaxial stress on the electron paramagnetic resonance of ruby
… be described by the addition of a term to the spin Hamiltonian of the form. The components of the G-tensor may be ascertained from the shift of the resonance field with strain at various directions in the crystal as a function of the angle between the applied magnetic field and the c-axis of …
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Statistical mechanical models for image processing
… of information processing, a special lattice spin Hamiltonian is used which is well suited for both source coding and for modeling information loss within the Bayesian framework. By applying a high-temperature expansion the parameter estimation problem is solved analytically using …
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Mössbauer investigations of high-spin ferrous heme proteins
… of heme proteins containing iron in the high-spin ferrous state is discussed. Paramagnetic hyperfine interactions, induced by strong applied magnetic fields, result in Mössbauer spectra that contain a wealth of information about the symmetry of the active site iron atomo Quantitative …
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Neutron scattering and magnetization studies of the spin correlations on the kagomé lattice antiferromagnet KFe₃(Oh)₆(SO₄)₂
… the 2D Ising transition. Above TN, the in-plane spin gap vanishes, and the system retains the SO(2) symmetry when measured with neutron scattering. On the other hand, specific heat measurements show a feature of the 2D Ising transition, since the underlying symmetry of the spin Hamiltonian is the …
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Paramagnetic resonance of transition group ions in crystals with the fluorite structure
… The isotropic spectra can be described by a spin Hamiltonian with g = 2.32 +/- 0.01, u=-0.Oil +/- 0.004, A = 27.5 +/- 1.2 x lO-4 cm-1 and U = 3.5 +/- 3.5 x 10-4cm-1. The superhyperfine splitting parameters are estimated to be Af = 2.85 x 10-4cm-1 and Bf = 5.97 x lO-4cm-1. Heat treatment of …
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Quantum spin transport in paramagnetic systems
… of magnetization and energy in systems of spins 1/2 on a lattice at high temperature. This work was motivated by recent experiments which observed "spin diffusion" among the dipolar coupled nuclear spins of the insulator calcium fluoride, under conditions where it was appropriate to neglect …
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A Mossbauer study of divalent iron in silver chloride crystals
… of the magnetic field measurements in the spin Hamiltonian formalism also were consistent with the vacancies occupying next-nearest neighbor sites with respect to the Fe+ + impurity. Methods for the calculation of theoretical Mossbauer spectra in fluctuating and static hyperfine fields are …
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A magnetic resonance study of iron in silver chloride
Th.e cubic electron spin resonance spectrum of Fe3+ in silver chloride has been studied at 1.3°K by the Electron Nuclear Double Resonance (ENDOR) technique. ENDOR lines from 6 to 24 megacycles were observed on each of the five electron spin resonance transitions and have been identified as lines …
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Electron spin resonance of trivalent neodymium pairs in anhydrous lathanum trichloride and lanthanum tribromide
Measurements of the electron spin resonance spectra of first- and second-neighbor Nd3+ pairs in LaC13 and LaBr3 were made at 4, 20K and 9 kMc/sec, These studies were made on crystals doped from 0,1 to 2, a atomic percent with enriched even-even isotopes of neodymium, The observed spectra can be …
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Very High Frequency EPR: Instrument and Applications
… g components are proportional to the $\pi$ spin densities on sulfur. In addition, the small proton hyperfine interactions of dibenzothiophene (DBT) are observed for the first time by continuous wave VHF EPR. A multifrequency approach, including auxiliary 2-4 GHz pulsed measurement, has shown …
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Electron paramagnetic resonance of myoglobin and related ferrous complexes
… which are not usually EPR active. These integer spin systems are nondegenerate in B = 0 and therefore split quadratically in B. In order to interpret the signals, a simulation program based on the spin Hamiltonian Illi = S·D·S + (3S.g.B was developed. The experimental EPR spectra are rather …
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Magnetic properties of transition metal dichloride - graphite intercalation compounds
… dominant coupling terms and anisotropies in the spin Hamiltonian, and magnetic neutron scattering is used to measure dynamic spin correlations above and below the critical temperatures. In addition, the atomic positions and structural dynamics of these compounds have been probed through x-ray and …
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Design and construction of an ultrasonic probe for use in a Cryo-Magnet NMR Spectrometer
… averaging of several components of the total spin Hamiltonian caused by restrictions placed on molecular motion within a solid. At present Magic Angle Spinning (MAS) NMR is the classical solid state technique used to reduce line broadening, but: this has associated problems, not least of which …
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