Nuclear hyperfine coupling table

Table 10.11. Nuclear hyperfine coupling constants (in MHz) for PF and related free radicals [37]...

Results for dipole moments are shown in Table 29. ° Clearly, coupled with good basis sets, correlated methods can do quite well for this property. Elsewhere, we have used relaxed density-based CC and MBPT methods to study spin densities and the related hyperfine coupling constants to evaluate relativistic corrections (Darwin and mass-velocity term) when impor-tant and to evaluate highly accurate electric field gradients to extract nuclear quadruple moments. 

While g-factors are measured by ESR, there are several methods like ESR, CW and pulsed ENDOR, special and general TRIPLE to determine the strength of the magnetic coupling i.e. hyperfine coupling) between the electronic and nuclear magnetic moments in liquid solution. The method chosen therefore depends both on the system and the available equipment. The various possibilities are summarised in Table 3.1. 

Equation (29) also applies to the case of IIN. However, naturally occurring iodine is monoisotopic with / = and the iodine nucleus can have any one of the six spin states m, = j, f, +f. The spin Hamiltonian that results is shown in matrix form in Table 4, where again the y axis is chosen as the quantizing axis for the nuclear spin. As before, r) terms mix states with Affj = 2 in the same electron spin manifold, whereas the hyperfine terms connect states in different electron spin manifolds with Am, = 0 or Am, = 1. The pro ton hyperfine terms (not included in Table 4) are relatively unimportant in this case, primarily because the — Ty energy separation is much larger. Thus, in spite of the large iodine hyperfine coupling, the simultaneous electron spin/proton spin transitions are weak and not observed at low power in triplet IIN. 

For polyatomic radicals in the gas phase the above Spin-Hamiltonian does not apply and four magnetic hyperfine coupling constants a, b, c, d are needed to describe the interaction between a nuclear and the electron spin. These are defined and explained in the introduction to the tables on inorganic radicals. 

Table 8. Calculated Hyperfine Coupling Constants (MHz), Nuclear Quadrupole Coupling Constants e qQ/h (MHz), and Asymmetry Parameters rj of the Large Model System PCU-L...

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