Laser and decay spectroscopy of the short-lived isotope $^{214}$Fr in the vicinity of the $N=126$ shell closure

Combined decay and laser spectroscopy measurements of the isotope $^{214}$Fr are reported, using the collinear resonance ionization spectroscopy (CRIS) technique at the ISOLDE facility at CERN. For the Iπ=(1−) spin assignment, the g-factor value of g($^{214}$Fr)=+0.241(16) corresponds to a relatively pure (π1h9/2 ⊗ ν2g9/2) ground-state configuration. An alternative interpretation with g($^{214}$Fr)=+0.144(10), for a (2−) spin assignment suggests a greater contribution of configuration mixing with the ν1i11/2 orbital. As the N=126 shell closure is passed, a kink is observed at the δ〈r2〉213,214 value, which is analogous to the behavior observed in the neighboring isotopic chains.