Abstract
A deep inelastic reaction between a thin self-supporting 19878Pt target and an 850MeV 13654Xe beam has been used to populate and study both neutron-rich nuclei around the beam and target masses and the reaction mechanism. An Ipi= 10+ isomeric state has been found in the N = 80 isotone 13656Ba with a measured half-life of 91 +/- 2ns. The structure of the predominantly (h11/2)-210+ isomer is discussed in terms of shell model and pair-truncated shell model calculations and compared to the even-Z, N = 80 isotones ranging from 13050Sn to 14868Er. A qualitative explanation of the observed dramatic decrease in the B(E2 : 10+ → 8+) value for the N = 80 isotones at 136Ba is given in terms of the increasing single-particle energy of the h11/2 neutron configuration as the proton sub-shell is filled. A 4-quasiparticle isomer has been observed in with a half-life of 188 +/- 38ns. The results are compared with blocked BCS Nilsson calculations which favour the Kpi= 15- interpretation. This isomer completes the even-A tungsten, 4-quasiparticle isomer systematics from A = 176 to 186. A high spin isomeric state has been found in the near spherical nucleus 19874W with a half-life of 36 +/- 2ns. The nature of this isomer has been interpreted from an examination of the systematics of platinum isotopes and neighbouring nuclei as a tentative Ipi= 12+ state from rotation-aligned, two neutron (i13/2)2configuration. Using prompt-delayed gamma-ray correlations, the complementary fragments of the reaction have been studied and used to identify new states in 19476Os. The angular momentum transfer to the binary fragments in the reaction has been investigated in terms of the average total gamma-ray fold versus the scattering angle of the recoils.