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Background: 139Pr is located in a transitional region of neutron number close to the N = 82 shell. The study of its high-spin states and collective bands is important for systematically understanding the nuclear structural characteristics in this region. Purpose: To investigate the high-spin levels and to search for oblate bands in 139Pr. Methods: The high-spin states of 139Pr have been studied via the reaction 124Sn(19F,4n) at a beam energy of 80 MeV. The experiment was carried out at the HI-13 Tandem Accelerator at the China Institute of Atomic Energy (CIAE). The data analysis was done by using the &ggr;-&ggr; coincidence method. Results: The level scheme of 139Pr has been expanded with spin up to 45/2ħ. A total of 39 new levels and 45 new transitions are identified. Four collective band structures at high-spin states have been newly established. From systematic analysis, one of the bands is proposed as a double decoupled band; two bands are proposed as oblate bands with &ggr; ∼ -60° another band is suggested as an oblate-triaxial band with &ggr; ∼ --90&dgr;. The other characteristics for these bands are discussed. Conclusions: A new level scheme in 139Pr has been established and the collective bands at high spin have been identified. The result shows that the strong oblate shape-driving effect is caused by neutrons at the high-spin states in 139Pr. [ABSTRACT FROM AUTHOR]

High-spin states of Pt190 have been reinvestigated using the 176Yb(18O, 4n) reaction at a beam energy of 88 MeV. The previously known positive parity band associated with the νi13/2-2νh9/2-1νj-1 (νj being νp3/2 or νf5/2) configuration has been revised and extended significantly. A new negative parity band has been established and proposed to be based on the νi13/2-3νj-1 configuration. Possible structure evolution of the yrast line from predominantly vibrational to rotational with increasing spin is discussed with the help of Eγ over spin curves. Additionally, calculations of total Routhian surfaces have been performed to investigate the band properties. [ABSTRACT FROM AUTHOR]

High-spin states in the odd-odd 194Au nucleus have been investigated using the 192Os(7Li, 5n) reaction at a beam energy of 44 MeV. The previously known structures built on the πh11/2-1⊗vi13/2-1 and πh11/2-1⊗ vi13/2-2vj configurations are extended to high-spin states, and a new Iπ = (20+) state associated with the πh11/2-1⊗vi13/2-2vh9/2-1 configuration is identified. Importantly, the πh11/2-1⊗vi13/2-2 band is found to exhibit normal signature splitting. The experimental results are compared with predictions from total Routhian surface and cranked shell-model calculations. Nonaxial shapes for the πh11/2-1⊗vi13/2-2 and πh11/2-1⊗vi13/2-2vh9/2-1 configurations are proposed. Possible reasons for the absence of signature inversion in the πh11/2-1⊗vi13/2-2 band in 194Au are discussed. [ABSTRACT FROM AUTHOR]

The high spin states .of 106Pd have been investigated with in-beam γ-ray spectroscopic methods using the l00Mo(11B, lp4n)106Pd reaction at a beam energy of 60 MeV. All earlier known bands were extended considerably and additional bands were identified. The configurations of these bands are discussed on the basis of the experimental aligned angular momenta and total Routhian surface calculations. Both two-quasineutron and two-quasiproton structures have been found in 106Pd. The nonyrast low-lying positive-parity band was interpreted as a γ-vibrational band. [ABSTRACT FROM AUTHOR]

Excited states in the stable nucleus 193Ir have been investigated through an in-beam γ-ray spectroscopic technique following the 192Os(7Li, α2n) reaction at a beam energy of 44 MeV. A level scheme built on the πh11/2 isomer has been extended to high-spin states using eleven newly observed γ transitions. The πh11/2 band is proposed to be formed by coupling an h11/2 proton to a core with large triaxial deformation. Three-quasiparticle states are suggested in 193Ir on referring to the similar states in 187Ir. The features of signature splitting in the πh11/2 bands of 187-193Ir are discussed with the help of total Routhian surface calculations. [ABSTRACT FROM AUTHOR]

The high spin states of 112In have been investigated with in-beam γ-ray spectroscopic methods using the 110Pd(7Li,5n)112In reaction at a beam energy of 50 MeV. A level scheme with three band structures has been established and their configurations are discussed. The positive-parity dipole band has been assigned as a magnetic rotation band. Particle-rotor model calculations have also been performed to interpret the rotational structures in 112In. [ABSTRACT FROM AUTHOR]