COMPLIS experiments : COllaboration for spectroscopy Measurements using a Pulsed Laser Ion Source

Laser spectroscopy measurements have been carried out on very neutron-deficient isotopes of Au, Pt and Ir, produced as daughter elements from a Hg ISOLDE beam. For these transitional region nuclides, the hyperfine structure (HFS) and isotope shift (IS) were measured by Resonance Ionization Spectroscopy (RIS). Magnetic moments μ, spectroscopic quadrupole moments Qs and changes of the nuclear mean square charge radius δ〈rc 2〉along isotopic series have been extracted. For some results, a detailed comparison with theoretical predictions is presented. (Springer

Hyperfine splitting and isotope shift in the optical transition

The laser-induced resonance fluorescence in an atomic beam was used in order to measure the hyperfine splitting of the 4ƒ76s2 8S7/2 and 4ƒ76s6p 6P5/2 levels in 151,153,155 Eu isotopes. The hfs constants A and B of the unstable 155Eu were determined for the first time: Aexp(155,8S7/2) = -8.78(3) MHz, Aexp(155,6P5/2) = -261.68(11) MHz and Bexp(155, 6P5/2) = -941(1) MHz. With these data and after corrections for second-order hyperfine structure perturbations the nuclear moments of 155Eu were deduced: μ(155) = 1.520(2) n.m. and Qs(155) = 2.494(20) b. In addition new and more precise values of the hfs constants of the excited state for the stable 151,153Eu were obtained. They are as follows: Aexp(151, 6P5/2 = -591.92(9) MHz, Bexp(151, 6P5/2) = -354.58(97) MHz and Aexp(153, 6P5/2) = -263.19(8) MHz, Bexp(153, 6P5/2) = -922.07(79) MHz. The hyperfine anomalies 151Δ153 = 0.74(4)% and 153Δ155 = 0.27(34)% were extracted from the corrected hfs constants