Nuclear levels of 183W studied with image and image reactions

The level structure of 183W has been studied using gamma–gamma coincidences from thermal neutron capture in 182W accompanied with the reaction image. From these data and those of previous studies a total of 76 levels and about 490 connecting γ-transitions have been established for energies below 2.4 MeV. An analysis based on the standard distorted-wave Born approximation (DWBA) provides the lj-angular momentum transfers and spectroscopic factors for 36 levels up to 2.2 MeV excitation energy. A large number of particle transitions indicate an influence of strong mixing between particle and probably hole states. The extra exchange of phonons across the Fermi surface leads to a fine structure in the fragmentation of most single particle strengths and at the same time has the effect of breakdown of the individual properties of Nilsson states. The extracted image and 2 (d, p) sum below 2 MeV has about the same magnitude as in 185,187W. It comprises a rather small fraction of the expected strengths. The observed states below 2 MeV are compared with predictions of the quasiparticle–phonon model. Of particular interest is the identification of “quasi-bands” with inverse spin sequence based on the state image at 622.8 keV; this indicates some transition aspects from rigid rotors of light W to γ-soft nuclei in the Os-Pt region.