Irradiation Damage Centers in Magnesiumhypophosphite

1975 ◽  
Vol 30 (8) ◽  
pp. 1044-1048 ◽  
Author(s):  
F. Köksal ◽  
H. Yüksel
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Unpaired Electron ◽  
Hyperfine Coupling ◽  
Irradiation Damage ◽  
Paramagnetic Species ◽  
Isotropic Hyperfine Coupling ◽  
Spin Resonance ◽  
Interaction Tensor ◽  
Gamma Irradiated

Abstract An analysis of the electron spin resonance spectra of gamma-irradiated crystals of magnesium-hypophosphite, Mg (H2PO2)2 · 6 H2O, has shown that the main long-lived paramagnetic species produced by gamma-irradiation are HPO2- and PO3- ionic radicals. The hyperfine interaction tensor of the phosphorous nucleus has the principal values T|| = 1674, T⊥ = 1221 Mc/s in HPO2- and T|| = 2490, T⊥ = 1847 Mc/s in PO3-. In HPO2- , interaction of the unpaired electron with the proton gives rise to an almost isotropic hyperfine coupling of 233 Mc/s. These results indicate that the orbitals occupied by the unpaired electron in both HPO2- and PO3= are sp3 -hybrid σ-orbitals centered on the phosphorous nuclei.

Electron Spin Resonance Linewidth Studies of Vanadyl Tetraphenylporphyrin

1993 ◽  
Vol 58 (6) ◽  
pp. 1294-1298
Author(s):  
Ali H. Al-Mowali ◽  
Alhan D. Girgees
Keyword(s):  
Electron Spin Resonance ◽  
Unpaired Electron ◽  
Hyperfine Coupling ◽  
Hyperfine Coupling Constant ◽  
Esr Spectra ◽  
Coupling Constant ◽  
Electron Spin Resonance Linewidth ◽  
Isotropic Hyperfine Coupling ◽  
Spin Resonance ◽  
Line Widths

The linewidths of the hyperfine components of the ESR spectra of vanadyl tetraphenylporphyrin in liquid toluene have been measured as a function of temperature and analyzed in detail. This has allowed the separate contributions to the observed ESR line widths from spin rotational, g tensor anisotropy, hyperfine anisotropy and unresolved nitrogen hyperfine coupling to be evaluated. These results have been used to estimate the size of the nitrogen isotropic hyperfine coupling constant and thus the extent of delocalization of the unpaired electron onto the nitrogen atoms.

ESR of Gamma Irradiated KHSO4 Single Crystal

1975 ◽  
Vol 30 (6-7) ◽  
pp. 750-753
Author(s):  
F. Köksal ◽  
H. Yüksel
Keyword(s):  
Electron Spin Resonance ◽  
Single Crystal ◽  
Electron Spin Resonance Spectrum ◽  
Electron Spin ◽  
Resonance Spectrum ◽  
Paramagnetic Species ◽  
G Factor ◽  
Spin Resonance ◽  
Potassium Hydrogen ◽  
Gamma Irradiated

Abstract Potassium hydrogen sulphate single crystal has been γ-irradiated at room temperature and its electron spin resonance spectrum recorded by changing the H0 static magnetic field, around an orthogonal axes system. The electron spin resonance spectrum is a single line with a slightly anisotropic g factor. The paramagnetic species has been identified as SO3- and the principal values of the g tensor has been determined as g1=g2=2.0060, g3 = 2.0045. Direction cosines of the principalvalues of the g tensor with respect to the chosen axes have been determined. The spin-orbit contribution to the g-factor has been explained.

scholarly journals EPR of Radiation Damage Centers in NaNO3, Sr(NO3)2, BaS, and MgC2O4·2H2O

1975 ◽  
Vol 30 (2) ◽  
pp. 269-270
Author(s):  
F. Köksal ◽  
H. Yüksel
Keyword(s):  
Electron Spin Resonance ◽  
Radiation Damage ◽  
Electron Spin ◽  
Room Temperature ◽  
Paramagnetic Species ◽  
Spin Resonance ◽  
Theoretical Predictions ◽  
Magnesium Oxalate ◽  
Gamma Irradiated

Abstract NaNO3, Sr(NO3)2, BaS, and MgC2O4·2 H2O powders have been gamma-irradiated at room temperature and their electron spin resonance spectra examined for paramagnetic species. The species identified were NO3 and NO2 radicals in the nitrates, SO2- and S in BaS, and H2C2O4- in magnesium oxalate. Theoretical predictions agree with these assignments.

scholarly journals Electron Spin Resonance of γ-Irradiated Taurine

1972 ◽  
Vol 50 (1) ◽  
pp. 43-49 ◽  
Author(s):  
G. Lind ◽  
R. Kewley
Keyword(s):  
Electron Spin Resonance ◽  
Hyperfine Interaction ◽  
Electron Spin ◽  
Unpaired Electron ◽  
Hyperfine Coupling ◽  
The Third ◽  
Coupling Tensor ◽  
Spin Resonance ◽  
Powder Samples ◽  
G Value

The 9.5 GHz electron spin resonance (e.s.r.) spectra of single crystal and powder samples of γ-irradiated taurine, [Formula: see text], have been recorded. Overlapping spectra from three distinct radicals are present. The first of these is the species SO3− with an isotropic g-value of 2.0035 and a 33S hyperfine coupling tensor with principal values 135.2, 99.2, and 97.9 G. The second radical is a π-electron species with the unpaired electron mainly on carbon and exhibiting hyperfine interaction from at least four protons, probably [Formula: see text] and with principal g-values 2.0021, 2.0027, and 2.0034. The third radical has principal g-values 2.0024, 2.0056, and 2.0097 and principal values of the 33S hyperfine tensor of 49.6, 9.1, and 1.2 G. The proposed structure for this radical is [Formula: see text]

Electron spin resonance studies of radiation damage. Part III. Gamma irradiated acetonitrile

1970 ◽  
Vol 48 (11) ◽  
pp. 1780-1781 ◽  
Author(s):  
F. P. Sargent
Keyword(s):  
Electron Spin Resonance ◽  
Radiation Damage ◽  
Electron Spin ◽  
Thermal Decay ◽  
Spin Resonance ◽  
Gamma Irradiated

The effects of photobleaching and thermal decay at 77 and 87 °K on the electron spin resonance spectra of gamma irradiated acetonitrile are reported.

Applications of ESR to Carbonaceous Materials

1982 ◽  
Vol 36 (1) ◽  
pp. 52-57 ◽  
Author(s):  
L. S. Singer ◽  
I. C. Lewis
Keyword(s):  
Free Radicals ◽  
Electron Spin Resonance ◽  
Low Temperature ◽  
Electron Spin ◽  
Paramagnetic Species ◽  
Carbonaceous Materials ◽  
Conduction Electrons ◽  
Spin Resonance ◽  
Higher Temperature ◽  
Low Temperature Pyrolysis

The applications of electron spin resonance (ESR) to carbonaceous materials are reviewed. The stable paramagnetic species observed in the products of low-temperature pyrolysis are odd-alternate neutral free radicals, whereas the unpaired spins of higher temperature carbons and graphites are primarily conduction electrons. The variety of ESR properties and phenomena requires special attention to techniques of measurement and interpretations of results. The relevance to the carbonization process of the free radicals observed by ESR is also discussed.

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