Hyperfine coupling tensor components

Hyperfine-coupling tensor components in Tesla for the intrinsic spin of iron, Spe = 3/2... 

The hyperfine coupling tensors of carotenoids were determined from the HYSCORE analysis of the contour line-shapes of the cross-peaks (Dikanov and Bowman 1995,1998, Dikanov et al. 2000), which provided the principal components of the tensors that appear to be rhombic. Such tensors are characteristic of planar conjugated radicals with the unpaired spin in a pz orbital of the carbon of the C-H group. 

X 7 0) with six independent components are widespread the polarizability and the hyperfine coupling tensors are well-known representatives. 

Here Ra is another orbital-reduction factor (0.5 < Ra < 1.0), P = 2gjvpe 3N. The anisotropic components of the hyperfine coupling tensor (a and a) are dehned as... 

Information from g-Tensor. Although the hyperfine coupling tensor is the most helpful piece of information derived from the ESR spectra, the g tensor is also informative, especially if the components are clearly distinguishable and deviate considerably from the free-spin value of 2.0023. 

In the ESR spectra of V0 (ex)-ZSM-5 and V (f)-ZSM-5 zeolites (which were registered at ambient temperature) notable differences could be observed in the parallel components of the tensor and in the elements on the main diagonals of the hyperfine coupling tensors (see Table 1). All these caused a displacement of the V (f)-ZSM-5 spectrum to higher fields as can be seen in Fig. 1. 

Determination of dissociation enthalpy. Components of the hyperfine coupling tensor could not be obtained since only a limited number of spectra could be fully interpreted. ... 

Where D and E are parameters which describe atomic energy level splitting from axial and non-axial interactions, the subscripts x, y and z identify the components of the atomic spin S and the nuclear spin I, fi and are the Bohr magneton and the nuclear magneton, B is the magnetic field, g and gfi are the electronic and nuclear -factors, A is the hyperfine coupling tensor, e is the charge on the proton and V and t are the principal component and the asymmetry parameter of the EFG. 

Bryce and Autschbach performed the accurate calculation of the isotropic and anisotropic (AT) parts of indirect nuclear spin spin coupling tensors for diatomic alkali metal halides (MX M = Li, Na, K, Rb, Cs X = F, Cl, Br, I) with the relativistic hybrid DFT approach. The calculated coupling tensor components were compared with experimental values obtained from molecular-beam measurements on diatomic molecules in the gas phase. Molecular-beam experiments offer ideal data for testing the success of computational approaches, since the data are essentially free from intermolecular effects. The hyperfine Hamiltonian used in analyzing molecular-beam data contains Hc IkDIi and //C4/a /l terms. The relationships between the parameters C3 and C4, used in molecular-beam experiments, and Rdd, A/, and used in NMR spectroscopy, are summarized in the following equations ... 

This phenomenon can be described invoking a second-rank hyperfine coupling tensor, 42,m [93], of components ... 

Using Neese s coupled-perturbed Kohn-Sham hybrid density functional (UPBEO, UBILYP) techniques, the gyromagnetic (g) and hyperfine tensor components of the thiophene-1,3,2-dithiazoly radical (TDTA) were computed and found to be in very good agreement with values from experimental determination <2006CPL(418)30>. 

The envelope curve depicted in Fig. 116 also applies to anisotropies caused by nuclei other than protons. As has been stressed already, such anisotropy generally arises from dipole-dipole interactions between electrons in p- or d-levels on the atom concerned. In that case, the hyper-fine coupling tensor should have axial symmetry, so that two of the three elements of the hyperfine tensor will be equal, and components similar to that in Fig. 106 will be detected. 

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