Electric Hyperfine Interactions

The expectation value of the nuclear radius in this equation has been replaced by / , a quantity that represents the radius of a spherically symmetric nucleus 

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In a detailed consideration of the full Hamiltonian, De Santis, Lurio, Miller and Freund [44] in paper II show that the required effective Hamiltonian for a given vibrational level v can be written as the sum of a part describing the rotational motion with electron spin interactions, and a part describing the magnetic and electric hyperfine interactions. The first part may be written ... 

The magnetic and electric hyperfine interactions for a molecule containing two equivalent 14N nuclei were discussed in detail in chapter 8 for the A 3 + state of N2. We summarise the results here, referring the reader to chapter 8 for a more thorough description. 

The electronic configuration and the local environment can be studied through the magnetic and electric hyperfine interactions which determine the features of the Mossbauer spectrum of the 57Fe nucleus. 

Electric Hyperfine Interactions Finally we discuss the oscillations of time spectra caused by the nuclear ground-state and excited-state splittings due to electric field gradients (EFGs). We limited our discussion in an axially symmetric EFG (asymmetric parameter tj = 0), and furthermore, the EFG axis is randomly oriented over the space. Then we can get the time spectrum [8] (Fig. 12.2)... 

Electric Hyperfine Interactions First, we will consider the SRPAC intensity with the presence of an axially symmetric quadrupole interaction caused by the interaction of the quadrupole moment of the excited nuclear state with an EFG produced by surrounding electrons and other nuclei. The direction of EFG is assumed to be isotropically distributed. In case of Fe, the excited-state spin I = 3/2, then the SRPAC intensity can be expressed as [12,25]... 

Atomic nuclei can be stretched like cigars (prolate shape) or compressed like discs (oblate shape). The deformation is described by the electric quadrii-pole moment Q (prolate Q > 0 oblate Q < 0). The principal interaction is, of course, the normal electrostatic (Coulomb) force on the charged nucleus monopole interaction). The differential interaction, which depends on the structure of the nucleus and on the valuation of the field across its finite extension, is of course very much smaller quadrupole interaction). It gives rise to an electric hyperfine structure. The energy contribution depends on the direction of the nuclear spin in relation to the electric field gradient. For the electric hyperfine interaction one obtains... 

Besides the electric hyperfine interactions, magnetic hyperfine interaction significantly modifies the profile of nuclear resonance lines as well. Such interaction occurs with the nucleus in the state with spin quantum number I >0 and is described by the Hamiltonian... 

Monard JA, Huray PG and Thomson JO 1974 Mossbauer studies of electric hyperfine interactions in u234, u236, u238. Phys. Rev. B 9(7), 2838—2845. 

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