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Showing 1 to 20 of 35 for “"Hyperfine coupling"”.
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Measurement of Hyperfine Coupling Constants of the 5d²D₃/₂ and 5d²D₅/₂ Levels in Atomic Cesium Using Polarization Quantum Beat Spectroscopy
<p>Accurate measurements of hyperfine constants have revealed effects that can not be explained by a simple hydrogenic picture of the alkali atoms such as cesium [1-3]. More precise experimental results and theoretical treatments are in demand for the alkali elements, especially for atomic cesium …
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Hyperfine Interaction of the Group IV Color Centers
… in previous works, a detailed theory of the hyperfine coupling to the nuclear spin is lacking. This work presents a complete theoretical model of the hyperfine coupling to the intrinsic dopant nucleus in the group IV-negative color centers, complete with ab-initio theoretical predictions of …
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Synthesis and electrochemistry of 1,2,4,6-thiatriazine radicals
… the radicals are highly diagnostic and display coupling to three unique nitrogen atoms, of which a small but very distinct influence on the hyperfine coupling constants from the remote aryl-substituents is seen. Solution electrochemistry assessed the redox tunability of the radicals to these …
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Electron paramagnetic resonance analysis of dimethyl amidogen in polycrystalline tetramethyl tetrazene.
… as the free radical dimethyl amidogen. The hyperfine coupling tensors were assigned on the basis of a polycrystalline line shape analysis. The radical exhibits axial symmetry with the parallel components of the tensors greater than the perpendicular components. The limits of error associated …
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Spectroscopic Studies of Some Semiquinone Radical Ions
… studied by ESR. The solvent dependance of the hyperfine coupling constants for the 3,3',5,5'-tetramethyl- derivative are reported and discussed in terms of an equilibrium between semi-quinone anions and hydrogen-bonded complexes of such anions with the hydroxylic solvent. The theory of Gendell, …
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Computer-assisted analysis of electron magnetic resonance spectra and the electron nuclear double resonance spectrum of isolated perylene cations
… discussed. Examples of its use in fitting the hyperfine coupling constants of ENDOR spectra are given.
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Development, validation, and application of new relativistic methods for all-electron unrestricted two-component calculations of EPR parameters
… all-electron scalar relativistic calculations of hyperfine coupling tensors at DKH2 level. Furthemore we have presented a general, relativistic two-component DFT approach for the unrestricted calculations of electronic g-tensors, based on DKH Hamiltonian. Additionally we have derived the …
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Magnetic resonance of cobalt(II) and iron(III): A Schiff's base and heme proteins
… In the first, the Co-59 nuclear quadrupole coupling constants for cobalt-doped nickelbis(benzoylacetone)ethylenediimine were determined by EPR spectroscopy. The three rotation axes for the three single crystals were not exactly perpendicular to each other, but their exact orientations were …
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Synthesis of 1-chloro-1,2,4,6-selenatriazines and some products of reduction
… dimer. EPR spectroscopy measured all radicals coupling to three unique nitrogen atoms with 7 broad lines. There is no resolvable hyperfine coupling to 77Se, 37Cl/19F and phenyl protons.
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Hyperfine structure and hyperfine transitions of helium-3
The hyperfine structure of 3He with an external magnetic field is precisely calculated by using double basis set wave functions. The comparison with available experiments effectively tests the theory of hyperfine structure. An exact diagonalization provides a comprehensive interpretation of the …
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Solution Properties of Some Iron and Copper Macrocycles.
… in DMSO indicate fast exchange and small hyperfine coupling constants. Solution magnetic susceptibilities of the complexes in DMSO indicate the absence of dimers.
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Electron Spin Echo and Millimeter Wave Epr Studies of Disordered Solids
… section of this study to measure weak nitrogen hyperfine coupling in a series of pyridine derivatives loosely bound to bis(benzoylacetonato)copper (Cu(benzac)$\sb2$) in solution. The ESE technique has also been employed to study weak, long range, unresolved, (matrix) hyperfine interactions in …
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ESR investigation of some free-radical adducts
The effect of steric strain on the esr hyperfine coupling constants of several free-radical adducts of perfluoropropene and perfluoro-2-butene were investigated. Silyl, hydroxyalkyl, thiyl and alkoxy free radicals, which were generated by photo-irradiation, reacted with these olefins to form …
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Engineering heme-copper and multi-copper oxidases for efficient oxygen reduction catalysis
… onset potential of oxygen reduction and the A// hyperfine of the T1 copper. The hyperfine coupling originates from the coupling between Cu nuclei and electron spin and a greater hyperfine coupling indicates a larger spin density localized on the Cu center, i.e., the Cu is more electron deficient …
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Measurement and Modeling of OPNMR Phenomena in GaAs Semiconductors
… of nuclear polarization and the nature of the hyperfine coupling that occurs between nuclear spins and nearby electrons. This dissertation examines the theory of optical pumping, polarization transfer, and experimental applications. Also included are observations of perturbations to the …
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Structure and microwave spectrum of the 2-cyano-2-propyl radical
… A program to calculate the fine splittings and hyperfine splittings due to the ¹⁴N nucleus and six protons was written. The spin rotation constants determined for the two species were E<sub>aa</sub>=-69.9, E<sub>bb</sub>=-36.1, E<sub>cc</sub>=2.7Mhz and E<sub>aa</sub>=-55.4, E<sub>bb</sub>=-32.6 …
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Predicting Kinetics of Spin-Dependent Reactions in an External Magnetic Field with Nonadiabatic Statistical Theory
… approaches for calculating spin-orbit coupling (SOC) that mediates transitions between electronic states with different spin multiplicities. The introduced effective, intermediate, and Ms-specific SOC approaches are employed to calculate the rate constants of spin transitions in the …
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Analyzing Electronic Correlation Effects in Molecules and Semiconductor Point Defects from First Principles Beyond Density Functional Theory
… of the FLOSIC-DFT to the computation of the hyperfine coupling terms, which are crucial for the realization of spin qubits and for interpreting electron paramagnetic resonance experiments. Chapter 4 turns to the application of a multiconfigurational method to describe the electronic …
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Studies of Solution Paramagnetic-Substrate Nuclear and Electron Intermolecular Interactions
… (DFT) calculation results with experimental hyperfine coupling constants leading to an improved understanding of solution dynamics. The short-lived solvent-solute interactions of the TEMPO-substrate molecules, such as transient complex formation, are governed by weak hydrogen-bonding …
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Spin projection of semi-empirical and ab initio unrestricted Hartree-Fock wavefunctions
… geometry was varied until the experimental hyperfine coupling constants matched hyperfine constants obtained from using both projected and unprojected UHF wavefunctions. The two types of calculations resulted in slightly different energies and geometries with the projected calculations …
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