Electric quadrupole interactions in rare-earth ions arising from electric field gradients due to valence electrons (q4f) and/or crystal fields external to the ion (qlat) are discussed. The contribution of the Sternheimer antishielding factors to both q4f and qlat are calculated for the Ce3+ ion using the method (based on the unrestricted Hartree-Fock formalism) reported earlier. The ionic antishielding factor (γ) is -73.5, and it is found that the total ionic contribution to the electric field gradient can be comparable in magnitude (and may be opposite in sign) with the valence electron contribution (augmented by the internal antishielding factor). The possible relation of these results to the temperature dependence of measured electric quadrupole interactions is noted.
ASJC Scopus subject areas
- Physics and Astronomy(all)