The energies of the excited states in very neutron-rich (42)Si and (41,43)P have been measured using in-beam gamma-ray spectroscopy from the fragmentation of secondary beams of (42,44)S at 39A MeV. The low 2(+) energy of (42)Si, 770(19) keV, together with the level schemes of (41,43)P, provides evidence for the disappearance of the Z=14 and N=28 spherical shell closures, which is ascribed mainly to the action of proton-neutron tensor forces. New shell model calculations indicate that (42)Si is best described as a well-deformed oblate rotor.

Collisions of Au on Au at incident energies of 150, 250 and 400 A MeV were studied with the FOPI-facility at GSI Darmstadt. Nuclear charge (Z ≤ 15) and velocity of the products were detected with full azimuthal acceptance at laboratory angles 1 • ≤ θ lab ≤ 30 • . Isotope separated light charged particles were measured with movable multiple telescopes in an angular range of 6 − 90 • . Central collisions representing about 1% of the reaction cross section were selected by requiring high total transverse energy, but vanishing sideflow. The velocity space distributions and yields of the emitted fragments are reported. The data are analysed in terms of a thermal model including radial flow. A comparison with predictions of the Quantum Molecular Model is presented.PACS: 25.70.Pq

The 0 þ 2 state in 34 Si has been populated at the GANIL-LISE3 facility through the decay of a newly discovered 1 þ isomer in 34 Al of 26(1) ms half-life. The simultaneous detection of e þ e À pairs allowed the determination of the excitation energy Eð0 þ 2 Þ ¼ 2719ð3Þ keV and the half-life T 1=2 ¼ 19:4ð7Þ ns, from which an electric monopole strength of 2 ðE0Þ ¼ 13:0ð0:9Þ Â 10 À3 was deduced. The 2 þ 1 state is observed to decay both to the 0 þ 1 ground state and to the newly observed 0 þ 2 state [via a 607(2) keV transition] with a ratio Rð2Gathering all information, a weak mixing with the 0 þ 1 and a large deformation parameter of ¼ 0:29ð4Þ are found for the 0 þ 2 state, in good agreement with shell model calculations using a new SDPF-U-MIX interaction allowing np-nh excitations across the N ¼ 20 shell gap.

Characteristics of the primary fragments produced in central collisions of129 Xe + nat Sn from 32 to 50 AMeV have been obtained. By using the correlation technique for the relative velocity between light charged particles (LCP) and fragments, we were able to extract the multiplicities and average kinetic energy of secondary evaporated LCP. We then reconstructed the size and excitation energy of the primary fragments. For each bombarding energy a constant value of the excitation energy per nucleon over the whole range of fragment charge has been found. This value saturates at 3 AMeV for beam energies 39 AMeV and above. The corresponding secondary evaporated LCP represent less than 40% of all produced particles and decreases down to 23% for 50 AMeV. The experimental characteristics of the primary fragments are compared to the predictions of statistical multifragmentation model (SMM) calculations. Reasonable agreement between the data and the calculation has been found for any given incident energy. However SMM fails to reproduce the trend of the excitation function of the primary fragment excitation energy and the amount of secondary evaporated LCP's.

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