Lanthanide Mossbauer resonances

Nuclear hyperfine parameters of important Mossbauer resonances in the actinides and lanthanides. 

Fig. 13. Plot of isomer shifts for different compounds of the important zero Mossbauer resonances in lanthanides and actinides. The contact density p(0) always increases from bottom to top. The actual values of shifts cannot be compared directly for the different resonances (see text), but their general tendencies can. In the lanthanides it is possible to separate roughly conducting and nonconducting compounds. In the actinides this is more difficult and needs more detailed analysis (see section 6). In all cases, however, conduction electrons produce an increase in contact density.

Parameters of selected Mossbauer resonances in lanthanides and actinides. 

Deuterium quadrupole coupling constants can also be obtained from electron nuclear double resonance (ENDOR).19 30 An observation of the hyperfine structure caused by quadrupole coupling in the electron paramagnetic resonance (EPR) spectrum, as for many lanthanide complexes, has not been reported for deuterium. The determination of nuclear quadrupole coupling constants from Mossbauer spectroscopy is not applicable to the deuterium nucleus. 

Most of the lanthanides have isotopes suitable for Mossbauer spectroscopy, c/., e.g., Wertheim (1964). In such experiments the resonant y-ray absorption is measured as a function of the relative velocity between the source and the sample. Spectral line shifts and splittings are related to the chemical nature and symmetry of the site of the ion. Spartalian and Oosterhuis (1973) have examined the spectrum of the Eu -transferrin complex. A single unshifted line was observed, which by itself offers little information. This is because at the low temperature (4.2 K) at which such experiments are normally carried out, only the ground-singlet level, of Eu is populated and it is hardly affected by the environment. Mossbauer spectra of other members of the lanthanide series should be more informative. 

Thus far it was tacitly assumed that the magnetic moments rest on the Mossbauer atoms. For Mossbauer spectroscopy with lanthanide and actinide resonances this is... 

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