Spectroscopy of neutron-rich P 34,35,36,37,38 populated in binary grazing reactions

The neutron-rich nuclei P34,35,36,37,38 were populated in binary grazing reactions initiated by a beam of S36 ions at 215 MeV incident on a thin Pb208 target. The combination of the PRISMA magnetic spectrometer and the CLARA array of escape-suppressed Ge detectors was used to detect γ rays in coincidence with projectile-like nuclear species. Further evidence to support the observed γ decay of excited states of the populated phosphorus isotopes is provided by γ-γ coincidence measurements based on the results of an earlier thick-target deep-inelastic experiment. Level schemes for P34,35,36,37,38 are presented and discussed within the context of state-of-the-art shell-model calculations. In particular, new spin and parity assignments are proposed for a number of excited states of P36. The evolution with neutron number of the energy difference of the low-lying Jπ=3/2+ and 1/2+ states in the odd-A isotopes of phosphorus, as well as the relationship to nuclear collectivity, is discussed. The evolution with neutron number of the shell-model wave functions of the first Jπ=1/2+, 3/2+, and 5/2+ states of the odd-A phosphorus isotopes and of the first Jπ=3-, 4-, and 5- states of the even-A isotopes is also explored.