Fermi Contact Hyperfine Constants for Rare-Earth Atoms and Ions from Moment-Perturbed Calculations

Abstract

Moment-perturbed calculations were carried out for the Fermi contact hyperfine constant for a selection of rare-earth atoms and ions. In the cases of neutral and divalent europium, a value that has the same sign as the experimental value but is larger in magnitude, was found. This is in disagreement with earlier published works of Bagus and Picart who, using an unrestricted Hartree-Fock approach, found a result of opposite sign compared to the experimental results. Results will be presented for divalent, trivalent, and neutral ions and atoms, and trends will be discussed.