Effect of Environmental Nuclei in Electron Spin Resonance Spectroscopy

Trammell, G. T.; Zeldes, Henry; Livingston, Ralph

doi:10.1103/physrev.110.630

Cited by 199 publications

(37 citation statements)

References 3 publications

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“…2d) the spacing between the central line and each satellite is reduced to about 1.3 G and the relative intensity is increased to about 18%. The decrease in the energy separation and increase in intensity with decreasing frequency is the behavior predicted for spin-flip transitions [12,13]. These transitions are not detectable in CW spectra of trityl-CD 3 at 250 MHz, which is consistent with calculations that show the energy separation at 250 MHz is too small to be resolved from the central line.…”

Section: Cw Line Shapes and G-vahtessupporting

confidence: 78%

“…In trityl-CD 3 there are no protons (except perhaps the carboxy[ate protons) in the mo[ecule and the structure is relatively compact so the distance of closest approach of solvent protons is about 0.7 nm [1,9]. The observed intensities of the spin-flip fines [12,13] are consistent with these dimensions. The intensities of these satellite lines in the Xband spectra are reduced when the exchangeable solvent protons are deuterated (Fig.…”

Section: Cw Line Shapes and G-vahtessupporting

confidence: 72%

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Multifrequency EPR of four triarylmethyl radicals

2005

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Continuous-wave spectra at W-band of four triarylmethyl (trityl) radicals at 100 K in 1:1 water-glycerol exhibit rhombic electron paramagnetic resonance spectra. The rigid-lattice line widths at W-band are only 3 to 5 times larger than at X-band or S-band, and fluid-solution [ine widths are much narrower than those for rigid lattice, which indicates that unresotved anisotropic nuclear .hyperfine couplings make significant contributions to the rigid-lattice line widths. Spin-flip lines ate observed in glassy-solution spectra at X-band and S-band, but notat W-band of 250 MHz. At 100 K T,, is dominated by spin diffusion of solvent protons and is independent of microwave frequency.Between about 130 and 170 K, I/T,, for trityl-CH 3 is enhanced by rotation of the methyl groups at a tate comparable to inequivalences in the hyperfine interaction. Motional averaging of anisotropic interactions enhances spin echo dephasing between about 200 and 300 K. The temperature dependence of 1/T~ is similar for the four radicals and is consistent with assignment of the Raman process and a local mode as the dominant relaxation processes. The similarity in T~ values at W-band and X-band supports this assignment.

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Section: Cw Line Shapes and G-vahtessupporting

confidence: 78%

Section: Cw Line Shapes and G-vahtessupporting

confidence: 72%

Multifrequency EPR of four triarylmethyl radicals

2005

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“…Six of the eight lines, those marked I, II, III, IIA, IIIA, IVA, expected for the CH3CHCOOH can be clearly seen despite overlapping by the main radical lines marked S and their ' spin-flip ' satellites [9] separated by + 13-6 Mc/s. A set of lines (I to IV) differ from the others (IA to IVA) by the hyperfine coupling to the fourth hydrogen and the 1 : 3 : 3 : 1 intensity pattern with equal spacing is just apparent.…”

Section: Radical Identificationmentioning

confidence: 91%

ENDOR studies on a rotating methyl group

Read

Whiffen

1967

Molecular Physics

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“…The intensity of these weaker resonances increased, with respect to the main lines, as the microwave power increased. Their separation was also field dependent, being 10.6 G at Ho = 3300 G and 9.4 G at Ho = 5300 G. This behavior is characteristic of features arising from the sympathetic spininversion of neighboring protons (10).…”

Section: ( a ) Radiation Damage In Hg(ii) Dopedmentioning

confidence: 89%

Spectroscopic Evidence for the Formation of the Mercurous Ion in Irradiated Acetates

Eachus¹,

Herring²

1971

Can. J. Chem.

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The Hg(1) center has been produced by y-irradiation both in HgQ doped cadmium acetate trihydrate and pure mercuric acetate. Both electron paramagnetic resonance and optical spectroscopy have been used to identify this species. The results indicate that the Hg(0 ion is produced in a covalent environment.La formation de HgO est produite par I'irradiation-y a la fois de Hg(I1) additionne d'acetate de cadmium trihydrate et d'adtate mercurique pur. Cette e s p k a eti identifik a la fois par resonance paramagnetique electronique et par spectroscopie optique. Les rksultats indiquent que l'ion Hg(0 est produit dans un environnement covalent.Canadian Journal of Chemistry, 49,2868 (1971) IntroductionThe effect of crystal structure on the production of radicals in irradiated acetates has been the subject of a recent publication (I). At 77 OK, the hydrated metal ,acetates gave methyl radicals as the primary product, whereas the anhydrous salts gave other species, usually the CH2C02-radical. The products of C-C bond rupture are stabilized by the hydrogen bond network present in hydrated salts. In this study the effect of the metal ion was ignored. However, recent results (2-4) have indicated that the metal ions can play an important role in the radiolysis of their salts. For example, it was necessary to invoke cationinvolvement to account for the unusual electron paramagnetic resonance (e.p.r.) spectra exhibited by polycrystalline Group IB and IIB metal carbonates and nitrates exposed to y-rays (2). The species (CdC0,)-, (Ag,CO,)-, (CdNO,), and (AgN0,)-, essentially covalent entities, were identified. Also, we recently reported that the exposure of the double salt CaCd(CH3.C02),6H,0 to y-rays at 77 O K resulted in the formation of Cd(1) and the methyl radical; on warming these centers decayed to produce the acetate fragment, CH2C02-(3,4). It would appear that the formation of low oxidation states of the metal ion, on irradiation, will occur when the cation present in the undamaged crystal has a high inelastic scattering cross section for electrons. The present investigation forms part of a comprehensive examination of the role of metal ions, which have

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Effect of Environmental Nuclei in Electron Spin Resonance Spectroscopy

Cited by 199 publications

References 3 publications

Multifrequency EPR of four triarylmethyl radicals

Multifrequency EPR of four triarylmethyl radicals

ENDOR studies on a rotating methyl group

Spectroscopic Evidence for the Formation of the Mercurous Ion in Irradiated Acetates

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