Experimental hyperfine shift

Fig. 4. Top Theoretical temperature dependence of the hyperfine shift of the H/3 protons of reduced spinach [Fe2S2] ferredoxin 151). The solid line corresponds to the situation where only one species exists in solution, whereas the dashed line corresponds to a situation where there is fast equilibrium between two species (in a 20/80 ratio) differing for the location of the extra electron 151). Bottom.-. Experimental temperature dependence of the H NMR shifts. The signals are labeled as in Fig. 2B.

FIGURE 5.7 Second-order hyperfine shift in the X-band EPR of the Cu(II)-Tris complex. The thin solid line is the experimental spectrum of 1.5 mM CuS04 in 200 mM Tris-HCl buffer, pH 8.0 taken at v = 9420 MHz and T = 61 K. Tris is tris-(hydroxymethyl)aminomethane or 2-amino-2-hydroxymethyl-l,3-propanediol. The broken lines are simulations using the parameters g = 2.047, gN = 2.228, Atl = 185 gauss. In the lower trace the second-order correction has been omitted. 

Fig. 8. A summary of 300- and 500-MHz H NMR spectra of 1.4 mAf human normal adult hemoglobin in 0.1 M phosphate at pH 7.1 in H20 or D20 at 29°C as a function of experimental conditions. (A) 300-MHz H NMR spectrum of oxy-Hb A in H20 over the entire spectral range from -30 to +90 ppm (X 100 means that the spectrum is expanded 100 times the original spectrum). (B) 300-MHz H NMR spectrum of deoxy-Hb A in H20 over the entire spectral range from -30 to +90 ppm (x 10 and X 100 mean that the spectrum is expanded 10 times or 100 times the original respective spectrum). (C) Hyperfine-shifted exchangeable proton reso-...

These ratios are, in fact, essentially independent of the principal quantum number n. Both numerator and denominator receive their main contribution close to the nucleus, where the behaviour of the atomic wavefunction is determined mainly by the orbital angular momentum. The situation is analogous to the relation between field isotope shifts and hyperfine structures, commonly used to analyse experimental isotope shifts [25,48,53]... 

Figure 33. King diagram for unperturbed (upper part) and perturbed (lower part) 6sns Sq Rydberg states. Open symbols refer to experimental isotope shifts, solid ones to data corrected for hyperfine-induced singlet-triplet mixing. The modified isotope shifts shown in Figure 33 were obtained using the data plotted in Figure 32a. (Taken from Ref. 62.)...

In analyzing shift measurements for such non rare-earth nuclei, account usually must also be taken of the classical dipolar field due to the rare-earth ionic moments. This field can be calculated on the basis of lattice sums, since the mean magnetization per ion is proportional to the susceptibility, and its effect subtracted from the measured total shift obtained experimentally in order to obtain the hyperfine shift. This procedure has been described in detail by Shulman and Knox (1960). 

Kim J, Middlemiss DS, Chernova NA, Zhu BYX, Masquelier C, Grey CP (2010) Linking local andvironments and hyperfine shifts a combined experimental and theoretical P and Li solid-state NMR study of paramagnetic Fe(lll) phosphates. J Am Chem Soc 132 16825-16840... 

Cahbration spectra must be measured at defined temperamres (ambient temperature for a-iron) because of the influence of second-order Doppler shift (see Sect. 4.2.1) for the standard absorber. After folding, the experimental spectrum should be simulated with Lorentzian lines to obtain the exact line positions in units of channel numbers which for calibration can be related to the hteramre values of the hyperfine splitting. As shown in Fig. 3.4, the velocity increment per channel, Ostep, is then obtained from the equation Ustep = D,(mm s )/D,(channel numbers). Different... 

Another reason to improve the HFS theory is provided by the perspective of reducing the experimental uncertainty of hyperfine splitting below the weak interaction contribution in (10.38). In such a case, muonium could become the first atom where a shift of atomic energy levels due to weak interaction would be observed [85]. 

Electron Transfer (ET) is a basic chemical process and is the fundamental step in oxidation-reduction reactions. Therefore it can be found in organic chemistry, inorganic chemistry, material science and biochemistry. The study of the structure and reactivity of radical ions, the primary species formed upon electron transfer of parent closed-shell systems, has been a topic of interest for several years. Initially, the research in this field focused on the experimental exploration of molecular structures in terms of their hyperfine structure. However, the interest has shifted during the past decade to the mechanistic studies of these reactive intermediates. 

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