Nuclear spectroscopy with fast exotic beams

Quadrupole collectivity in the proximity of the doubly-magic shell closure at N = Z = 28 has been studied using intermediate-energy Coulomb excitation of ⁵⁴,⁵⁶,⁵⁹Ni and ⁵²Fe. The results will be summarized and discussed in comparison to large-scale shell model calculations.

A complementary experimental approach sensitive to the single-particle structure of exotic nuclei, one-neutron knockout at intermediate beam energies, has been applied to the proton-rich N = 16 isotones ³⁴Ar, ³³Cl and ³²S as well as to ³²Ar where the knockout residue ³¹Ar is the last particle-bound Z = 18 isotope. The reduction of single-particle strength (‘‘quenching’’) compared to shell-model calculations using the USD interaction is discussed in the framework of correlation effects beyond effective-interaction theory.