Electron paramagnetic resonance experiment

I. B. Goldberg, T. M. McKinney, Principles and techniques of electrochemical-electron paramagnetic resonance experiments in Laboratory Techniques in Electroanalytical Chemistry (Eds. P. T. Kissinger, W. R. Heineman),... 

The electron paramagnetic resonance experiments on the yttrium ceramics, on the other hand, are ambiguous. In the study by Murrieta et al. [55], the EPR signal of YBa2Cu307 sample was interpreted as a superposition of two different lines attributed to the Cul and Cu2 sites. In some other studies of yttrium ceramics, the EPR signal was not detected or was attributed to an impurity phase [56]. Thus, Ilirther more refined EPR experiments are needed to confirm the location of the unpaired spin in the cluster. 

Principles and Techniques of Electrochemical-Electron Paramagnetic Resonance Experiments - 901... 

Hildenbrand K (1995) Spin-trapping studies of the reaction of the sulfate radical ion with N1-substituted pyrimidine bases. Comparison with continuous-flow electron paramagnetic resonance experiments.) Chem Soc Perkin Trans 2 2153-2162 Hildenbrand K, Schulte-Frohlinde D (1997) Time-resolved EPR studies on the reaction rates of per-oxyl radicals of polyfacrylic acid) and of calf thymus DNA with glutathione. Re-examination of a rate constant for DNA. Int J Radiat Biol 71 377-385 Hildenbrand K, Behrens G, Schulte-Frohlinde D, Herak JN (1989) Comparison of the reaction OH and S04- radicals with pyrimidine nucleosides. An electron spin resonance study in aqueous solution. J Chem Soc Perkin Trans 2 283-289... 

The X-ray powder diffraction data reveal that for the Fe(CO) and the Scherzer-Fort preparations that bulk a-Fe is present. Electron paramagnetic resonance experiments indicate in all cases that ferromagnetic iron is present in these reduced samples. The X-ray data also reveal that these samples are crystalline after each of these synthetic procedures and that crystallinity is not lost when these samples are photolyzed or thermally treated. 

Electron paramagnetic resonance experiments also support the existence of ferromagnetic iron particles. X-ray powder diffraction experiments, electron microscopy, and surface analysis measurements show the existence of both metals on the surface before and after reduction. We know the particle size again is quite large, although there is a wide digtribution in these samples, ranging from 30 A to about 150 A. 

Future Areas of Research. There are certain future experi-ments that are very important for further understanding of the work reported here. The most important ones concern lifetime measurements of the quenching of isopropanol. Secondly, the mechanism of quenching must be understood. Electron paramagnetic resonance experiments will be helpful here. More bulk photolyses and other organic quenchers need to be studied, especially variable size quenchers, in order to help understand diffusional processes in these zeolites. We are presently studying the surfaces of these zeolites with ion scattering spectrometry and secondary ion mass spectrometry. The preliminary results indicate that we... 

The spin polarization effect was first identified in free radicals, and in particular in conjugated hydrocarbons [48, 49]. In such radicals (the simplest one being the planar CH3 molecule), where the unpaired electron is supposed to occupy a n type MO, the EPR (Electron Paramagnetic Resonance) experiment evidenced the existence of spin density on the nuclei of the hydrogen atoms. This seems in contradiction with the nuUity of the SOMO in the plane of the molecule and thus on the H atom nuclei. This observation could interpreted only if on leaves the closed-shell description of the core . 

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