Spin-dipole contribution

An exception is the so-called triplet-type properties such as the Fermi-contact and spin-dipole contributions to indirect spin-spin coupling constants (for a discussion, see Ref. 44). 

Ramsey theory (p. 666) diamagnetic effect (p. 668) paramagnetic effect (p. 668) coupling constant (p. 668) direct spin-spin interaction (p. 669) diamagnetic spin-orbit contribution (p. 669) paramagnetic spin-orbit (p. 670) spin-dipole contribution (p. 670)... 

Theoretical study on cation dinitrogen complexes [N2---X---N2] X + = H +, Li +, Na+, Be +, Mg + performed at the MP2/6-311 + + G(d,p) level by Alkorta and Elguero included calculations of Vnn, and Vnn spin-spin couplings. The effect of orbital instabilities for spin-symmetry breaking perturbations, namely the Fermi-contact and spin-dipole contributions to the indirect nuclear spin-spin couplings has been investigated by Auer and Grass. The calculations have been performed for the CO and N2 molecules. 

Given the specific, internuclear dipole-dipole contribution terms, p,y, or the cross-relaxation terms, determined by the methods just described, internuclear distances, r , can be calculated according to Eq. 30, assuming isotropic motion in the extreme narrowing region. The values for T<.(y) can be readily estimated from carbon-13 or deuterium spin-lattice relaxation-times. For most organic molecules in solution, carbon-13 / , values conveniently provide the motional information necessary, and, hence, the type of relaxation model to be used, for a pertinent description of molecular reorientations. A prerequisite to this treatment is the assumption that interproton vectors and C- H vectors are characterized by the same rotational correlation-time. For rotational isotropic motion, internuclear distances can be compared according to... 

D is the zero-field splitting tensor, a traceless, rank-two tensorial quantity. The ZFS tensor is a property of a molecule or a paramagnetic complex, with its origin in the mixing of the electrostatic and spin-orbit interactions (80). In addition, the dipole dipole interaction between individual electron spins can contribute to the ZFS (81), but this contribution is believed to be unimportant... 

In addition to the isomer shift and the quadrupole splitting, it is possible to obtain the hyperfine coupling tensor from a Mossbauer experiment if a magnetic field is applied. This additional parameter describes the interactions between impaired electrons and the nuclear magnetic moment. Three terms contribute to the hyperfine coupling (i) the isotropic Fermi contact, (ii) the spin—dipole... 

An example of such a solution spectrum was given in Fig. 1. The dipole contribution to the hyperfine interaction drops out in Eq. (121) leaving the solution A to be primarily determined by the contact term which measures the amount of s character in the spin-moment distribution. 

The dipole contribution to the nuclear spin-spin coupling constants in Section 8.3 comes from the more general expression... 

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