ESR linewidth

Fig. 12a, b A comparison of the temperature dependence of the X-band ESR linewidth in a nonferromagnetic a modification and b ferromagnetic a modification... 

When excess of ZnTPP (1.0 X 10 3 M) is used for the oxidation with Ru(bpy)33+ (5.0 X 10 4 M) at 233 K, the ESR linewidth becomes broader than the spectrum obtained in the equimolar condition (Fig. 13.2c). The computer simulation spectrum with a broader linewidth is shown in Fig. 13.2d. The line broadening results... 

Figure 2(b) compares the thermal evolution of the MgB2 ESR linewidth (this work and Refs. [17, 18]) with its dc resistivity extract from Ref. [19]. The linewidth is measuring the spin scattering rate and the resistivity gives the... 

In isotropic three-dimensional conventional metals 2e Tle and the linewidth has a temperature dependence which is similar to that of the resistivity [13]. The dominant process leading to the spin-lattice relaxation rate, l/Tle, comes from the modulation of spin-orbit interactions by phonons. Elliot [14] has shown that in this case, the ESR linewidth, AHpp, is... 

To give an order of magnitude A 4-mg sample with a volume of 3 mm3, of a material with a 13-mG ESR linewidth, would have a signal-to-... 

In Fig. 23 we show the ESR linewidths AHpp for the six compounds discussed above. The larger widths of (TMTSF)2X salts, compared to the (ET) Re04 derivatives, is due to the larger spin-orbit coupling in Se than in S. Apart from this, the linewidths show the following features. 

Fig. 23. A comparison of the ESR linewidths of various (TMTSF)2X, X = monovalent anion, and ET Re04 salts.

ESR linewidths for g 2 species in poly lOH extracts and polyacetylene at different temperatures, all values in gauss. 

Several formalisms have been applied to relaxation in exchanging radicals. Principal among these are modifications of the classical Bloch equations (8, l ) and the more rigorous quantum mechanical theory of Redfield al. (8 - IJ ). When applied in their simplest form, as in the present case for K3, both approaches lead to the same result. Since the theory has been elegantly described by many authors (8 - 12 ), only those details which pertain to the particular example of K3 will be presented here. Secular terms contribute to the ESR linewidth (r) and transverse relaxation time (T ) by an amount... 

Figure 5. Comparison of measured ESR linewidths (V) with assumed temperature dependence in trimer correlation times (tJ a, tc — uT b, tc —...

ESR is very useful in the study of dynamic properties of membrane components because of its high sensitivity and favorable time scale. Early ESR studies of short-range lateral diffusion in membranes were based on Heisenberg exchange (HE) effects of nitroxide spin-label line width. The HE contribution to the ESR linewidth is given for nitroxides by = )dDNACf, where d is the encounter dis-... 

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