Proton scattering from the unstable nuclei 30S and 34Ar: structural evolution along the sulfur and argon isotopic chains☆

Abstract Proton elastic and inelastic scattering angular distributions to the 2 1 + and 3 1 − collective states of the proton-rich nuclei 30 S and 34 Ar were measured at 53 MeV/ A and 47 MeV/ A , respectively, using secondary beams from the GANIL facility and the MUST silicon strip detector array. Data for the stable 32 S nucleus were also obtained at 53 MeV/ A for comparison. A phenomenological analysis was used to deduce the deformation parameters β p,p′ for the low-lying collective excitations. A microscopic analysis was performed by generating matter and transition densities from self-consistent QRPA calculations. Configuration mixing calculations based on a collective Bohr Hamiltonian were also performed. DWBA and coupled-channel calculations using microscopic optical potentials built from these densities and the JLM interaction are compared to the data. There is no indication for the presence of proton skins in these nuclei. The microscopic calculations are extended to the even–even sulfur and argon isotopes from A =30 to A =40, and A =34 to A =44, respectively, and compared to available experimental results. On the basis of this analysis predictions are made for the 42,44 S and 46 Ar nuclei concerning ground state and transition densities.