Exchange, coupling constant

The two spins 5a and 5b are assumed to be local, associated with the two sites a and b, respectively. The parameter J is the so-called exchange-coupling constant, which expresses the strength of the (super)exchange interaction between the... 

Finally, it is noteworthy that in addition to the isotropic part of spin coupling as treated above, there may also be an anisotropic contribution due to the presence of anisotropic exchange [114] or dipole interaction [106]. In this case, the exchange coupling constant is replaced by a tensor... 

Ab initio DDCI2 (difference-dedicated configuration interaction) calculations seem to provide accurate estimations of the magnetic exchange coupling constants, as demonstrated for the doubly azido-bridged nickel(II) dimer [Ni2(terpy)2(/i-l,l-N3)2]2+.2133... 

Figure 6.1 Stick spectra for a dinitroxide biradical with a= 13 G for various values of the exchange coupling constant J. (Several very small, widely spaced resonances have been omitted for J=2A and J=5A.)...

In summary, nuclear spin exchange effects are to be expected in the NMR of the heavier elements in the solid state. From the exchange coupling constants information on the nature of electronic wave functions in solids may be obtained. 

The Heisenberg exchange coupling constants J can be calculated from the BS DFT solutions utilizing the approaches of Noodleman (87), Ruiz (116), or Yamaguchi (117—119), which differ in the assumptions made regarding the strength of the... 

Another example of detailed insight into the behavior of calculated 55Mn HFCs comes from investigating the dependence of these quantities on the secondary (not nearest-neighbor) exchange coupling constants. Such a study would test, for example, the validity of simplifications that exclude the secondary... 

Fig. 18. Dependence of isotropic 55Mn hyperfine parameters (MHz) on the Jbc/Jab ratio (left) and the magnitude of the secondary exchange coupling constants Jac, Jad (right) for [MninMnIV3(bpy)6]s+.

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