Signature splitting inversion and backbending in 80Rb

High spin states of 80Rb are studied via the fusion-evaporation reactions 65Cu+19F, 66Zn+18O and 68Zn+16O with the beam energies of 75 MeV, 76 MeV and 80 MeV, respectively. Twenty-three new states with twenty-eight new \gamma transitions were added to the previously proposed level scheme, where the second negative-parity band is significantly pushed up to spins of 22^{-} and 15^{-} and two new sidebands are built on the known first negative-parity band. Two successive band crossings with frequencies 0.51 MeV and 0.61 MeV in the \alpha=0 branch as well as another one in the \alpha=1 branch of the second negative-parity band are observed for the first time. Signature inversions occur in the positive- and first negative-parity bands at the spins of 11\hbar and 15\hbar, respectively. The signature splitting is seen obviously in the second negative-parity band, but the signature inversion is not observed. It is also found that the structure of the two negative-parity bands is similar to that of its isotone ^{82}Y. Signature inversion in the positive-parity yrast band with configuration \pi g_{9/2} \otimes \nu g_{9/2} in this nucleus is discussed using the projected shell model (PSM)

Decay of 1.643 h

The decay of 95Ru has been investigated by means of γ-ray spectroscopy. The 95Ru nuclei were produced by the reaction 92Mo( α, n) 95Ru at a beam energy of 17MeV. High-purity Ge detectors have been used singly and in coincidence to study γ-rays in the decay of 95Ru to 95Tc. 132 γ-rays are reported, among them, energies and intensities for 127 transitions have been determined. A decay scheme of 95Ru with 31 levels is proposed which accommodates 127 of these transitions. Spins and parities for three new levels are proposed from calculated log ft values, measured γ-ray branching ratios, and in-beam experiment results of the daughter nucleus 95Tc. Combining with the high-spin states observed by in-beam γ-ray spectroscopy of previous decay works, the structure of the excited states of 95Tc is discussed in the framework of the projected shell model

Decay of \chem{^{83}Sr} and level structure of \chem{^{83}Rb}

The excited states of the \chem{^{83}Rb} nucleus were investigated in radioactive decay of \chem{^{83}Sr}. The level scheme was established and for a number of levels spin-parity assignments are suggested on the basis of $\log ft$ values and $\gamma$-branching ratios. Combining with the high-spin states observed by the in-beam $\gamma$-ray spectroscopy of a previous decay work, the structure of the excited states of \chem{^{83}Rb} is discussed in the framework of the projected shell model

High spin states in stable nucleus \u3csup\u3e84\u3c/sup\u3eSr

High spin states of 84Sr were populated through the reaction 70Zn(18O, 4n)84Sr at 75 MeV beam energy. Measurement of excitation function, γ-γ coincidences, directional correlation from oriented state (DCO) ratios and γ-transition intensities were performed using eight anticompton HPGe detectors and one planar HPGe detector. Based on the measured results, a new level scheme of 84Sr was established in which 12 new states and nearly 30 new γ-transitions were identified in the present work. The positive-parity states of the new level scheme were compared with the results from calculations in the framework of the projected shell model (PSM). One negative-parity band was extended to spin I π=19- and it can be found that in the high spin states, the γ-transition energies show the nature of signature staggering. The negative-parity band levels are in good agreement with deformed configuration-mixing shell model (DCM) calculations. © 2010 Science China Press and Springer-Verlag Berlin Heidelberg

Triaxial shape in Os-Pt region from ground states to collective rotational states

In order to study the deformation of the nuclei which belongs to the transitional region between strongly deformed and spherical nuclei, the calculations of the total Routhian surfaces by means of the pairing-deformation- frequency self-consistent cranked shell model were carried out in order to investigate shape evolution in even-mass Os and Pt isotopes ( 176-202Os and 182-204Pt) starting from the static nuclear ground states. It is found that some nuclear ground states such as in 196Os and 188-194Pt are neither oblate nor prolate. Instead, the ground-state minima in these nuclei are axially asymmetric in shape. In addition, a complementary approach is used to extract equilibrium γ0 value (nonaxially symmetric equilibrium shape parameter), which support our predictions. © 2010 World Scientific Publishing Company