Proton hyperfine interactions

REINHARD KAPPL, GERHARD BRACIC, AND JURGEN HUTTERMANN 

The position of the g-tensor is different, on the other hand, in the Rieske iron sulfur protein, in which, in the [2Fe2S] cluster, two of the cysteine residues coordinated to one iron are exchanged against histidines (cf Fig. 1, left bottom structure). Here gmax lies along the iron-iron interconnection vector, as was proposed on theoretical grounds and supported from single-crystal EPR data [19,22]. We have recently analyzed the proton ENDOR data and found clearly the respective symmetry 

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In a study of the isotropic proton hyperfine interaction constants for various Fe(R2Dtc)3 complexes and their redox behavior, a simple relationship... 

Figure 9.34. Laser magnetic resonance spectrum of CH in its a 4 state recorded in parallel polarisation (AMj = 0) with the 166.6 /un laser line of CH2F2. The rotational transition is N = 2 <—, and the quintet fine structure may be understood by reference to the energy level diagram in figure 9.33. The lines marked with an asterisk arise from an impurity species the doublet splittings of the CH lines are due to proton hyperfine interaction [69].

Figure 10.58. Observed spectrum for J = 5/2 — 3/2 inthe 2 FI3/2 ground state of the OH radical [68]. The three components are due to proton hyperfine interaction, as discussed in the text. See also figure 10.59 for an energy level diagram, with transitions, but without hyperfine splitting.

J = 511 -> 511 rotational transition in the 03/2 state. The small doubling of each resonance arises from the proton hyperfine interaction. 

Aono, S., Higuchi, J. (1962). Hyperconjugation and Proton Hyperfine Interaction Angular Dependence. Progress of Theoretical Physics, 28, 589-598. 

Fermi contact term is the dominant proton hyperfine interaction. When qg > 1 for positive shifts, substantial polarization contributions will also be present. In contrast, a negative Knight shift with qg =q is strong evidence for only the d-band polarization interaction which clearly indicates N j(Ep) Ng (Eg) since H f(s) > H f(d),... 

Poppl A, Kevan L. 1996. A practical strategy for determination of proton hyperfine interaction parameters in paramagnetic transition metal ion complexes by two-dimensional HYSCORE electron spin resonance spectroscopy in disordered systems. J Phys Chem 100 3387-3394. 

Although proton hyperfine interactions are by far the most common in aromatic radicals, a great deal of information about spin densities can also be derived from hyperfine interactions with and so forth. 

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