Electron paramagnetic resonance (EPR) spectra of Mn++ at normal and defect sites of a crystalline ZnS lattice

1973 ◽  
Vol 16 (10) ◽  
pp. 1375-1379
Author(s):  
A. Ya. Yakunin ◽  
I. V. Shtambur ◽  
A. S. Kushnir ◽  
S. A. Omel'chenko
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Epr Spectra ◽  
Paramagnetic Resonance ◽  
Defect Sites ◽  
Electron Paramagnetic

Electron Paramagnetic Resonance of Radicals Formed during Milling

1960 ◽  
Vol 33 (2) ◽  
pp. 462-468 ◽  
Author(s):  
S. E. Bresler ◽  
S. N. Zhurkov ◽  
E. N. Kazbekov ◽  
E. M. Saminskiĭ ◽  
E. E. Tomashevskiĭ
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Gamma Rays ◽  
Epr Spectra ◽  
Mechanical Degradation ◽  
Present Communication ◽  
Surface Layers ◽  
Paramagnetic Resonance ◽  
Mechanical Destruction ◽  
Electron Paramagnetic

Abstract It is well known that during the mechanical degradation of polymers there takes place scission of molecular chains and the formation of macroradicals. It is of considerable interest to study the electron paramagnetic resonance (EPR) spectra of the macroradicals produced by milling, and to compare them with the spectra of the macroradicals formed in the process of polymerization, and also during the irradiation of polymers by gamma rays and neutrons. We may endeavor to compare the amount of macroradicals formed with the extent of mechanical destruction (for instance with the area of the new interface which is formed). In addition, as was found by experience, the macroradicals formed by mechanical scission are good models for the investigation of reactivity since practically all of them are in the newly formed surface layers and are therefore very accessible to various chemical influences. They enter easily into reaction with various agents present in the medium since in this process diffusion from the surface is found in practice not to be a predominating factor. In the present communication we give the first EPR results obtained on mechanically degraded polymers.

Characterization of titanium dopants in sodium alanate by electron paramagnetic resonance spectroscopy

2005 ◽  
Vol 20 (12) ◽  
pp. 3265-3269 ◽  
Author(s):  
Meredith T. Kuba ◽  
Sandra S. Eaton ◽  
Christine Morales ◽  
Craig M. Jensen
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Epr Spectra ◽  
Minor Amount ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Dehydrogenation Kinetics ◽  
Electron Paramagnetic ◽  
Kinetics Of

Electron paramagnetic resonance (EPR) spectra were obtained for samples of Ti-doped NaAlH4 subjected to different numbers of cycles of dehydrogenation/re-hydrogenation. Ti is observed to evolve from its initial Ti(III) state through a series of Ti(0) species during the first 5 cycles. Although the conversion of Ti(III) to Ti(0) occurs much more readily for TiCl3-doped samples than those prepared with TiF3, in both cases the evolution of Ti follows the same sequence that involves 3 distinguishable Ti(0) species and ends in the predominance of the same single Ti(0) species. The spectrum of a sample of NaAlH4 containing 2 mol% of cubic Al3Ti is distinctly different than any of those observed for the Ti(0) species that arise during the hydrogen cycling of the hydride. The major changes in the nature of the predominant Ti species have little if any effect on the dehydrogenation kinetics, which strongly suggests that the profoundly enhanced hydrogen cycling kinetics of Ti-doped NaAlH4 are due to a Ti species present in only a relatively minor amount.

Growth and EPR properties of KSm(WO4)2 and KEr(WO4)2 single crystals

Open Physics ◽  
2012 ◽  
Vol 10 (2) ◽  
Author(s):  
Grzegorz Leniec ◽  
Tomasz Skibiński ◽  
Slawomir Kaczmarek ◽  
Przemyslaw Iwanowski ◽  
Marek Berkowski
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Hyperfine Structure ◽  
Single Crystals ◽  
Angular Dependence ◽  
Growth Conditions ◽  
Magnetic Interactions ◽  
Epr Spectra ◽  
Paramagnetic Resonance ◽  
Temperature Dependences ◽  
Electron Paramagnetic

AbstractGrowth conditions and electron paramagnetic resonance investigations of two well oriented KSm(WO4)2 and KEr(WO4)2 single crystals have been presented and discussed. Hyperfine structure of Sm3+ ion was detected and analyzed for angular and temperature dependences. EPR spectra of KEr(WO4)2 and its angular dependence showed the presence of 5 magnetically nonequivalent Er centers in the crystal. A change in the type of magnetic interactions was analyzed using mixed (Gaussian and Lorentzian) fits of the EPR spectra.

Electron Paramagnetic Resonance of Gamma Irradiation Damage Centres in Acetyl and Carbamyl-β-Methyl Choline Chloride

2003 ◽  
Vol 2003 (1) ◽  
pp. 26-27
Author(s):  
Şemsettin Osmanoğlu ◽  
M. Halim Başkan
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Gamma Irradiation ◽  
Choline Chloride ◽  
Epr Spectra ◽  
Irradiation Damage ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic

The EPR spectra of 7-irradiated powders of acetyl-β-methyl choline chloride (AβMCCl) and carbamyl-β-methyl choline chloride (CβMCCl) indicated the existence of the [Me3NĊMeCH2OCOMe]Cl radical in the former and of the [Me3NĊMeCH2OCONH2]Cl radical in the latter.

LOCAL STRUCTURE CHARACTERIZATION OF GADOLINIUM DOPED AMORPHOUS AND CRYSTALLINE ALUMINA

2001 ◽  
Vol 15 (12n13) ◽  
pp. 375-384 ◽  
Author(s):  
S. SIMON
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Local Structure ◽  
Sol Gel ◽  
Structure Characterization ◽  
Epr Spectra ◽  
Paramagnetic Resonance ◽  
Amorphous Alumina ◽  
Electron Paramagnetic ◽  
Crystalline Alumina

The evolution of local structure during the transition from amorphous to crystalline states of gadolinium doped alumina is characterized by electron paramagnetic resonance (EPR). The EPR spectra of samples belonging to the (1 - x) Al 2 O 3x Gd 2 O 3 system, where x = 0.002, 0.01, 0.05 and 0.1, show that the gadolinium ions are relatively uniformly distributed in amorphous alumina granules prepared by sol–gel methods. First, gadolinium doped α-alumina appears on the surface of the γ-alumina granules where there are low coordinated (N < 6) gadolinium species. The transition from γ- to α-alumina is postponed by the presence of high coordinated gadolinium (N < 6) ions inside of γ-alumina granules.

Electron paramagnetic resonance, optical and magnetic studies of Tb 3+ in lanthanide nicotinate dihydrates

1987 ◽  
Vol 413 (1845) ◽  
pp. 515-528 ◽  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Optical Absorption ◽  
Ground State ◽  
Zeeman Effect ◽  
Optical Absorption Spectroscopy ◽  
Site Symmetry ◽  
Magnetic Studies ◽  
Paramagnetic Resonance ◽  
Defect Sites ◽  
Electron Paramagnetic

Optical absorption and fluorescence, magnetic susceptibility and electron magnetic resonance experiments have been made of Tb 3+ , 4f 8 , ions in lanthanide nicotinate dihydrate single crystals. Optical absorption spectroscopy in undiluted terbium nicotinate dihydrate (TbND) indicates that the ground state of Tb 3+ , 7 F 6 , is a singlet exhibiting a quadratic Zeeman effect, and this is confirmed by the observation of a temperature-independent Van Vleck paramagnetism below 4.2 K. This is what one would expect for a non-Kramers ion in a crystal field of no symmetry. In spite of this, electron paramagnetic resonance (epr) is observed from Tb 3+ ions both in dilute LaND containing 0.01 mole fraction of Tb and in TbND. In the dilute material, in spite of the absence of site symmetry, the results show a nearly degenerate non-Kramers doublet with a g value of 17.2(8), close to the maximum possible value of 12 g j ; the ground state must therefore be predominantly M j = ±6. The epr in TbND arises from some type of defect site involving two interacting dissimilar Tb 3+ ions. The spectrum of Tb 3+ ions observed by optical fluorescence is also attributed to defect sites.

scholarly journals A tentative approach to the molecular structure of humic acids: the spectral evidence for a derivation of humic acids from plant-borne esters. 1. The electron paramagnetic resonance (EPR) spectra.

1979 ◽  
Vol 27 (1) ◽  
pp. 79-91 ◽  
Author(s):  
G. Minderman
Keyword(s):  
Molecular Structure ◽  
Electron Paramagnetic Resonance ◽  
Humic Acids ◽  
Epr Spectra ◽  
Paramagnetic Resonance ◽  
Spectral Evidence ◽  
Heterogeneous Polymers ◽  
Electron Paramagnetic

It is suggested, from the evidence of EPR spectra, that humic acids are heterogeneous polymers of mixed esters derived from tannins. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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