High spin states of 128La have been studied through the fusion-evaporation reaction 118Sn(14N,4n) 128La at a beam energy of 69 MeV. A positive-parity side band with the same configuration as that of the yrast band has been identified. Moreover, it is noted that the energy separation △E(I) = E(I)side-E(I)yrast of all doublet bands reported in odd-odd nuclei in the A～130 mass region exhibit a staggering pattern systematically, and they stagger up at even-spin and stagger down at odd-spin.
Angular-momentum-projected energy surface calculations for A ≈ 110 nuclei indicate three distinct energy minima occurring at different angular-momenta. These correspond to normal, super-, and hy- per-deformed shapes coexisting in one nucleus. 110Pd is studied in detail, with a quantitative prediction on super- and hyper-deformed spectra by the Projected Shell Model calculation. It is found that several other neighboring nuclei in the A-110 mass region, with the neutron number around 64, also exhibit clear super- and hyper-deformation minima in the projected calculation.
SUN Yang1,2, ZHANG JingYe3, LONG GuiLu4,5 & WU ChengLi6,7 1 Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China
High spin states in the odd-odd nucleus 124 Cs have been investigated through the fusion-evaporation reaction 116 Sn(11 B,3n) 124 Cs with a beam energy of 45 MeV.A new rotational band is established and assigned as the high-k configuration of πg 9/2 [404]9/2 +νh 11/2 [523]7/2.Some structures linking to this band have also been observed.According to the results of the excitation energy systematics,the lowest level of this band is assigned as 9,and the 8 isomer bandhead has not been observed.Another isomer with a half life of 6.3 s has also been observed with its new decay paths established.Its excitation energy is raised by 79 keV,but its I π is not changed.
