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We report on the first low-energy Coulomb excitation measurements with radioactive I 6 ÿ beams of odd-odd nuclei 68;70 Cu. The beams were produced at ISOLDE, CERN and were post-accelerated by REX-ISOLDE to 2:83 MeV=nucleon. rays were detected with the MINIBALL spectrometer. The 6 ÿ beam was used to study the multiplet of states (3 ÿ , 4 ÿ , 5 ÿ , 6 ÿ ) arising from the 2p 3=2 1g 9=2 configuration. The 4 ÿ state of the multiplet was populated via Coulomb excitation and the BE2; 6 ÿ ! 4 ÿ value was determined in both nuclei. The results obtained illustrate the fragile stability of the Z 28 shell and N 40 subshell closures. A comparison with large-scale shell-model calculations using the 56 Ni core shows the importance of the proton excitations across the Z 28 shell gap to the understanding of the nuclear structure in the neutron-rich nuclei with N 40. Radioactive beams provide great opportunities for investigating the nuclear structure away from the stable nuclei. One of the regions of the nuclear chart that has attracted a considerable interest in the past years is the one close to 68 Ni [1][2][3][4][5][6][7][8]. Coulomb excitation experiments with radioactive beams of even-even isotopes showed that the coupling of a few extra particles to the 68 Ni core induces large polarization effects [2,3]. These effects were associated with a weakening of the Z 28 and N 40 gaps when neutrons start filling the 1g 9=2 orbital [2]. Beyond N 40, results of -decay measurements in the neutronrich [69][70][71][72][73] Cu isotopes revealed a dramatic and sudden lowering of the 1f 5=2 orbital with the increased occupancy of the 1g 9=2 orbital [4]. Referred to as monopole migration, this energy shift was interpreted as originating from the residual proton-neutron interaction and it is expected to have profound implications on the structure of the doubly magic nucleus 78 Ni [4,5].Shell-model calculations using different effective nucleon-nucleon interactions were used in order to understand the observed properties in the nuclei around 68 Ni and predict the evolution of the shell structure towards 78 Ni [5][6][7][8]. The calculations indicated that the values of the Z 28 and N 40, 50 energy gaps strongly depend on the effective interaction used. A consistent understanding of the evolution of the nuclear structure in these regions requires also experimental information such as excitation energies and transition rates in the odd-A and odd-odd nuclei.

The hyperfine structure splitting and the isotope shift in the ,~ = 266 nm transition of Pt isotopes within the mass range 183 _< A ~< 198 have been determined by Resonance Ionization Mass Spectroscopy (RIMS) in combination with Pulsed-Laser Induced Desorption (PLID). The Pt isotopes were obtained at the on-line isotope separator ISOLDE-3/CERN as daugthers of the primarily produced Hg isotopes. Magnetic moments, quadrupole moments, and changes in the mean-square charge radii are deduced and compared with results of a particle-triaxial rotor model and mean field calculations. Good agreement with experimental data (including nuclear level schemes and transition probabilities) can only be obtained if triaxial shape is admitted. The calculations yield a smooth transition in the shape of odd-A Pt nuclei from a slightly deformed, nearly oblate ~95pt via triaxial 193-187pt to a strongly deformed nearly prolate t77pt.

On-line resonance-ionization mass spectrometry has been applied to determine the isotope shift and hyperfine structure of [185][186][187][188][189] Au and 189Aum in the 6s 2S 1 / 2 -6p 2Pl/2 (A =268 nm) transition. The Au atoms were obtained as daughters of mass-separated Hg isotopes produced at the ISOLDE facility at CERN ionized by a three-color, two-step resonant photoionization process, detected and n1ass selected by time of flight. A drastic change of the nuclear charge radius was observed between 187Au and 186Au, which is interpreted as an onset of strong deformation of f3~0.25 in 186Au and 185 Au.