Isomeric low-lying states were identified and investigated in the 75 Cu nucleus. Two states at 61.8(5)-and 128.3(7)-keV excitation energies with half-lives of 370(40)-and 170(15)-ns were assigned as 75m1 Cu and 75m2 Cu, respectively. The measured half-lives combined with the recent spin assignment of the ground state allow one to deduce tentatively spin and parity of the two isomers and the dominant multipolarities of the isomeric transitions with respect to the systematics of the Cu isotopes. Shell-model calculations using an up-to-date effective interaction reproduce the evolution of the 1/2 − , 3/2 − , and 5/2 − states for the neutron-rich odd-mass Cu isotopes when filling the νg 9/2 . The results indicate a significant change in the nuclear structure in this region, where a single-particle 5/2 − state coexists with more and more collective 3/2 − and 1/2 − levels at low excitation energies.

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To investigate the behavior of the N = 14 neutron gap far from stability with a neutron-sensitive probe, proton elastic and 2(1)+ inelastic scattering angular distributions for the neutron-rich nucleus 22O were measured using the MUr à STrip detector array at the Grand Accélérateur National d'Ions Lourds facility. A deformation parameter beta(p,p') = 0.26 +/- 0.04 is obtained for the 2(1)+ state, much lower than in 20O, showing a weak neutron contribution to this state. A microscopic analysis was performed using matter and transition densities generated by continuum Skyrme-Hartree-Fock-Bogoliubov and quasiparticle random phase approximation calculations, respectively. The ratio of neutron to proton contributions to the 2(1)+ state is found close to the N/Z ratio, demonstrating a strong N = 14 shell closure in the vicinity of the neutron drip line.

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In an experiment at the SISSI/LISE facility of GANIL, we used the projectile fragmentation of a "Kr primary beam at 73 MeV/nucleon to produce new isotopes of astrophysical interest. We obtained clear evidence for the existence of the five new isotopes Ga, 4As, Kr, and ' Sr. However, we did not find any evidence for Br, whereas comparable nuclei were observed with more than 1000 counts. The isotope 9Br is thus deduced to be a proton-unbound nucleus with a half-life shorter than about 100 ns.

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