Hyperfine structure of 4ƒ^N 6s^2 configurations in ^159Tb, ^161,163Dy, and ^169Tm

Abstract

The atomic-beam, laser-rf, double-resonance method has been used to measure the hyperfine structure in excited levels of the 4fN 6s2 configurations of the neutral rare earths 159Tb, 161,163Dy, and 169Tm. On combining the new information with earlier results for the lower levels, it is possible to extract many of the hyperfine radial integrals 〈〈r−3〉xy). The present results, together with work published during the last year on 165Ho and 167Er, now make it possible to plot the values of the integrals completely across the 4f shell. The ab initio calculations of Lindgren and Roien reproduce the magnetic-dipole hfs integrals well but appear to overestimate the electric-quadrupole integrals 〈r−3〉11 and 〈r−3〉13.