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Static, Low-Frequency, and Pulsed Magnetic Fields in Biological Systems
Published in James C. Lin, Electromagnetic Fields in Biological Systems, 2016
As reviewed recently by Ueno and Shigemitsu (2007), several biophysical and biochemical effects can be expected when biological systems are simultaneously exposed to SMFs and other forms of energy such as light and radiation (Ueno and Harada 1986; McLauchlan and Steiner 1991). Photochemical reactions produced by a radical pair intermediate are expected to show SMF effects that arise from an electron Zeeman interaction; an electron–nuclear hyperfine interaction (Fermi-contact interaction); or a hyperfine interaction mechanism, such as an electron-exchange interaction in a radical pair intermediate (Hata 1976; Tanimoto et al. 1976, 1989; Schulten 1982a; Nagakura and Molin 1992; Natarajan and Grissom 1997; Nagakura, Hayashi, and Azumi 1998; Hayashi 2004).
Electron spin resonance spectroscopy
Published in D. Campbell, R.A. Pethrick, J.R. White, Polymer Characterization, 2017
D. Campbell, R.A. Pethrick, J.R. White
The interaction between a nuclear spin I and an electron spin S may be shown to be composed of two parts: the isotropic and anisotropic contributions. The isotropic part arises from the Fermi contact interaction and implies that isotropic hyperfine splitting will be observed only if there is a finite probability of finding unpaired electron spin density at the interacting nucleus. The anisotropic part of the hyperfine interaction is the angular dependent electron spin–nuclear spin, dipole–dipole interaction and is only observed in solids. In liquids and gases, rapid tumbling of the radicals averages these interactions to zero.
Matrix Isolation of Hand Datoms: Physics and Chemistry From 1.5 To 0.1 K
Published in Leonid Khriachtchev, Physics and Chemistry at Low Temperatures, 2019
Vladimir V. Khmelenko, David M. Lee, Sergey Vasiliev
where ri is the distance from the electron to coordination shell i, θ is the angle between the applied field H0 and the vector pointing from the atomic free radical to the molecule, ge and gn are the g-factors of the electron and nuclear spins, βe and βn are the Bohr and nuclear magnetons, and Asup is the isotropic superhyperfine coupling associated with the Fermi contact interaction between the electronic wave function of the atom and the nuclear wave function of the molecule.
Black-body radiation-induced photodissociation and population redistribution of weakly bound states in H2 +
Published in Molecular Physics, 2022
The hyperfine structure of the rovibrational levels in H is described using Hund's case with the coupling scheme: The coupling of and to form is caused by the Fermi contact interaction, which is the leading term in the hyperfine Hamiltonian with of the order of MHz. The coupling constants were computed using the adiabatic nuclear wave functions and the electron densities from Ref. [18] (see Tables A1 and A2 in Appendix 1). For X we find excellent agreement with the experimentally determined value from Ref. [10].