Diffusion magnetic field effects

A study involving iron amalgams in acidic and alkaline media indicates a magnetic field effect on the Tafel slope, probably due to a complex interaction of the magnetic field with amalgam formation, diffusion, and hydrogen evolution. Experimental results obtained with cupric sulfate solutions show no magnetic field effect on the transfer coefficient... 

The microscopic approach has been particularly successful in the treatment of the Hall effect in electrolytes, summarized in an earlier overview [5]. As in the case of Hall conductivity, the magnitude of the magnetic field effect on diffusion is very small [6,7] but not negligible in a rigorous sense. The Llelmezs-Musbally formula [6] based on the theory of irreversible thermodynamics for bi-lonic systems ... 

MHD theory [9-14] has been applied extensively [e.g. 15-21] in conjunction with convective diffusion theory [22-26] to the analysis of external magnetic field effects in the hydrodynamic and concentration boundary layer existing at the electrode/electrolyte interface [2,5,27]. 

Fig. 8.9 Semilogarithmic plot of the ratio of fluorescence intensity obtained in the simulation (line) and adjacent average smoothing (circle) using 2 pairs (cyan) 5 pairs (magenta) 10 pairs (green) and 15 pairs (blue). Cations were linearly distributed with a mean spacing of a 40 A c 100 A and e 150 A. In b, d and f the solid red line is the analytically calculated magnetic field effect using the T values in Table 8.8, with T2 5 ns. Anions were distributed using a Gaussian distribution with mean zero and standard deviation of 80 A. A mutual diffusion coefficient (D ) of 0.325 A ps was used for S7 / c-RH+...

The high external magnetic field can mix the zero-field spin sublevels and therefore will change the rate constants of the T-S transitions [65]. This concept can be applied to triplet chromophores in biopolymers with slow rotational diffusion. Moreover, the Zeemann perturbation can induce additional mechanisms for the T-S mixing [65, 66]. The standard Liouville equation for spin density matrix [65] can be used for prediction of magnetic field effects on spin-selective photoprocesses and enzymatic reactions if the ZFS and hyperfine coupling parameters are properly interpreted in connection with the T-S transitions rate constants. 

Figure 8 Effects of spin diffusion. The NOE between two protons (indicated by the solid line) may be altered by the presence of alternative pathways for the magnetization (dashed lines). The size of the NOE can be calculated for a structure from the experimental mixing time, and the complete relaxation matrix, (Ry), which is a function of all mterproton distances d j and functions describing the motion of the protons, y is the gyromagnetic ratio of the proton, ti is the Planck constant, t is the rotational correlation time, and O) is the Larmor frequency of the proton m the magnetic field. The expression for (Rjj) is an approximation assuming an internally rigid molecule.

Fig. 3.7.1 Schematic of the DDIF effect in porous medium. The black areas are solid grains and the white areas are pore space. Diffusing spins in permeating fluid sample the locally variable magnetic field B(r) (solid contours sketched inside pore space) as it diffuses.

The second piece of evidence in distinguishing rods in a magnetic field to those out of the magnetic field was the rotational diffusion coefficient of the rod. It was the rotational diffusion coefficient that revealed the effect that an applied magnetic field had on a nanorod moving non-Brownian outside a field (2000 ° /s) and in it (70 ° /s). 

Fig. 8. The water-proton spin-lattice relaxation rates vs. magnetic field strength plotted as the Larmor frequency at 282 K for hexacyanochromate(II) ion ( ), trioxalatochromate(III) ion ( ), and trimalonatochromate(III) ion (A). The lines were computed using translational diffusion models developed by Freed with and without the inclusion of electron spin relaxation effects 54,121).

---