EPR Data on Ni(II) Doped Cu(II) Acetate Monohydrate Single Crystals: Evidence of Ni2+ — Cu2+ Exchange-Coupled Pairs

1984 ◽  
Vol 39 (11) ◽  
pp. 1061-1065 ◽  
Author(s):  
E. Buluggiu
Keyword(s):  
Single Crystals ◽  
Hyperfine Coupling ◽  
Hyperfine Coupling Constant ◽  
Magnetic Behaviour ◽  
Coupling Constant ◽  
Paramagnetic Resonance ◽  
Strongly Coupled ◽  
Definite Difference ◽  
Electron Paramagnetic ◽  
Made In

Electron paramagnetic resonance measurements on nickel(ll) doped copper(ll) acetate mono­hydrate single crystals have been made. In the liquid helium temperature range, spectra have been observed which may be assigned to Ni2+-Cu2+ strongly coupled mixed pairs in the state of total spin S = 1/2. This result represents a definite difference of magnetic behaviour from the case of the nickel(II) doped dicopper(II) tetra(μ-benzoato-O,O′)bis(quinoline) complex, which has the same sandwich dimeric structure but shows spectra indicative of a S=3/2 state. Apart from this difference, unusual EPR data are found such as pronounced misalignments of g with respect to the relevant pair axes and very large values of the hyperfine coupling constant of the copper nucleus, which characteristically recall that case.

A Study of the Effect of Solvent and Temperature on the Electron Paramagnetic Resonance Parameters and Linewidths of Copper(II)bis(Diethyldithiocarbamate)

1974 ◽  
Vol 52 (24) ◽  
pp. 4016-4024 ◽  
Author(s):  
F. Geoffrey Herring ◽  
Robert L. Tapping
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Hyperfine Coupling ◽  
Hyperfine Coupling Constant ◽  
Rotational Correlation Time ◽  
Coupling Constant ◽  
Paramagnetic Resonance ◽  
Axial Ligation ◽  
Effect Of Solvent ◽  
Isotropic Hyperfine Coupling ◽  
Electron Paramagnetic

The effect of varying solvent and temperature on the e.s.r. parameters and linewidths of copper(II) bis(diethyldithiocarbamate) has been studied. The temperature and solvent dependences of the isotropic hyperfine coupling constant (a0) have been interpreted in terms of vibronic and axial ligation effects. The rotational correlation time, τR, of Cu(DEDC)2 has been measured in the solvents employed. The values of τR measured at 300 K have been used to obtain the anisotropic interaction parameter, κ, which is found to correlate roughly with the dipole moment and molar refractivity of the solvent.

scholarly journals Electron Paramagnetic Resonance (EPR) Detection of Nitric Oxide Produced during Forebrain Ischemia of the Rat

1994 ◽  
Vol 14 (5) ◽  
pp. 715-722 ◽  
Author(s):  
Teiji Tominaga ◽  
Shinya Sato ◽  
Tomoko Ohnishi ◽  
S. Tsuyoshi Ohnishi
Keyword(s):  
Nitric Oxide ◽  
Electron Paramagnetic Resonance ◽  
Hyperfine Coupling ◽  
Hyperfine Coupling Constant ◽  
Forebrain Ischemia ◽  
Coupling Constant ◽  
Paramagnetic Resonance ◽  
Rat Forebrain ◽  
Electron Paramagnetic

To detect if nitric oxide (NO) is produced in rat forebrain ischemia, we applied an electron paramagnetic resonance (EPR) NO-trapping technique. We also performed a detailed characterization of the technique. Diethyldithiocarbamate (DETC) and Fe-citrate were used as NO-trapping reagents. Under controlled ventilation, forebrain ischemia was produced by occlusion of both carotid arteries combined with hemorrhagic hypotension at 50 mm Hg for 15 min. DETC and Fe were administered 30 min prior to the onset of ischemia. During ischemia, the cerebral cortex was removed, and EPR samples were prepared. At liquid nitrogen temperatures, the NO-Fe-DETC signal (a triplet signal centered at g = 2.039 with the hyperfine coupling constant aN of 13 G) was detected overlapping Cu-DETC signals. By perfusing various concentrations of an NO-generating agent, 1,1-diethyl-2-hydroxy-2-nitrosohydrazine, into the rat brains, the amount of the “trapped NO” was calibrated. The size of the NO-Fe-DETC signal was well correlated with the NO concentrations in the perfusate (correlation coefficient r = 0.998, p < 0.01). Based on this calibration curve, it was found that the amount of trapped NO during forebrain ischemia increased to seven times that of the control (control n = 5, forebrain ischemia n = 4, p < 0.005).

The β-phosphorus hyperfine coupling constant in nitroxide: part 3: titration of water by electron paramagnetic resonance

2015 ◽  
Vol 13 (46) ◽  
pp. 11393-11400 ◽  
Author(s):  
Gérard Audran ◽  
Lionel Bosco ◽  
Paul Brémond ◽  
Teddy Butscher ◽  
Jean-Michel Franconi ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Organic Solvent ◽  
Hyperfine Coupling ◽  
Hyperfine Coupling Constant ◽  
Coupling Constant ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

Titration of a few percent of water in an organic solvent is possible due to a large difference in aP.

The Electron Paramagnetic Resonance Spectrum of γ-Irradiated Dimethyl Malonic Acid

2004 ◽  
Vol 59 (1-2) ◽  
pp. 103-104 ◽  
Author(s):  
Biray Aşik ◽  
Mehmet Birey
Keyword(s):  
Magnetic Field ◽  
Electron Paramagnetic Resonance ◽  
Electron Paramagnetic Resonance Spectrum ◽  
Single Crystals ◽  
Malonic Acid ◽  
Hyperfine Coupling ◽  
Resonance Spectrum ◽  
Coupling Constants ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

The electron paramagnetic resonance of γ -Irradiated single crystals of dimethyl malonic acid [(CH3)2C(COOH)2] has been studied for different orientations of the crystal in a magnetic field. The radicals produced by gamma irradiation have been investigated between 123 and 300 K. The spectra were found to be temperature independent, and radiation damage centres were attributed to [(CH3)2C(COOH)2]+ radicals. The g factor and hyperfine coupling constants were found to be almost isotropic with average values g = 2.0036, a(COOH)2 = 0.5 mT, a(CH3)2 = 2.1 mT, respectively, and spin density ρ = 91% of the [(CH3)2C(COOH)2]+ radical.

Optically Induced Paramagnetic Defects in PbTiO3 Single Crystals

1993 ◽  
Vol 310 ◽  
Author(s):  
W.L. Warren ◽  
B.A. Tuttle ◽  
B.N. Sun ◽  
Y. Huang ◽  
D.A. Payne
Keyword(s):  
Single Crystals ◽  
Lead Titanate ◽  
Hyperfine Coupling ◽  
Axially Symmetric ◽  
Crystal Field Theory ◽  
Paramagnetic Resonance ◽  
Inherent Feature ◽  
First Time ◽  
Electron Paramagnetic ◽  
Perovskite Lattice

AbstractOptical excitations for trivalent platinum (5d7, t6e) and trivalent Pb (6s1) ions in lead titanate single crystals have been observed for the first time by electron paramagnetic resonance (EPR). The g and hyperfine coupling, A, tensors of Pt+3 defects were found to be axial: gil∥ = 1.938, g⊥ = 2.478, A∥ = 0.0164 cm−1, and A⊥ = 0.0324 cm−1. Analysis of the EPR spectra by crystal field theory indicates that the Pt+3 ions are in tetragonally distorted (elongated) octahedral sites, strongly suggesting that they substitute for the central Ti+4 ions in the perovskite lattice. Axially symmetric Fe+3 impurities were also observed in the crystals, and they also appear to substitute for the Ti+4 cation. Identification of Pb+3 in these single crystals further shows that holes trapped at Pb+2 ions are an inherent feature of Pb-based perovskite ferroelectrics.

Electron Paramagnetic Resonance of Cu2+ in KHC03 Single Crystals

1999 ◽  
Vol 54 (3-4) ◽  
pp. 177-179 ◽  
Author(s):  
F. Köksal ◽  
İ. Kartal ◽  
B. Karabulut
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Single Crystals ◽  
Ground State ◽  
Room Temperature ◽  
Hyperfine Coupling ◽  
Charge Compensation ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

The electron paramagnetic resonance spectra of Cu2+ doped KHC03 single crystals were studied at room temperature. The results indicate a substitutional entrance of the Cu2+ ions in place of the magnetically inequivalent K+ sites. The charge compensation is supposed to be fulfilled by proton vacancies. The hyperfine lines were well resolved and the 65Cu hyperfine coupling tensors were also found. The ground state of Cu2+ indicates the dominance of the dx2-y2 orbital and, therefore, elongation of the polyhedron, similar to a lengthened octahedron.

EPR of VO2+ in ZnTiF6 · 6H2O

1996 ◽  
Vol 51 (4) ◽  
pp. 245-248
Author(s):  
Geetha Jayaram ◽  
V. G. Krishnan
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Single Crystals ◽  
Spin Hamiltonian ◽  
Paramagnetic Resonance ◽  
Tutton Salts ◽  
Bonding Parameters ◽  
Superhyperfine Structure ◽  
Vanadyl Ion ◽  
Electron Paramagnetic

Abstract Electron Paramagnetic Resonance (EPR) studies have been carried out on the vanadyl (VO2) ion doped in single crystals of ZnTiF6 • 6H2O. The spectra indicate the presence of one set of eight lines characteristic of only one occupation site. The V-O bond orientation is along one of the three Zn-H2O bond directions in the trigonally distorted [Zn(H2O)6] octahedra. This behaviour is unlike that reported for vanadyl ion substituting for the M(H2O)6 sites in the Tutton salts, alums and AlCl3 • 6H2O. The Spin-Hamiltonian and bonding parameters for the [VO(H2O)5] complex have been evaluated. The hyperfine linewidths are 0.8 mT at 300 K and 77 K. No proton superhyperfine structure was observed at both these temperatures.

Sign in / Sign up

Export Citation Format

Share Document