Investigation of particle-core coupling in 69Ge

Competing single-particle and collective behavior in71Se

“…A similar pattern is observed in other nuclei with 5 2 − ground states such as 69 Se [11], 69 Ge [25], and 71 As [26][27][28], where the most strongly populated 13 2 − state shows two competing E2 decays to two relatively closely spaced 9 2 − states. The 581.6-and 621.8-keV decay branches of the 1378.7-keV state lead to respective states at 797.1 and 756.9 keV, which likely correspond to the 796.4-and 756.7-keV states observed in Ref.…”

“…Taking the g 9/2 neutron excitation energy as 260 keV in 71 Se (i.e., the energy difference between the 9 coupling of a g 9/2 neutron to the 7 − state at 3915 keV in 70 Se. Similar interpretations of an unpaired g 9/2 particle coupled to its corresponding even-even core have been proposed for analogous states in 69 Ge [25] and 71 As [26].…”

“…The experimental |Q t | values obtained for bands 1-4 in 71 Se are also compared with those measured within similar band structures in 69 Ge [25], 73 Se [12], and 73 Kr [46] in Fig. 9.…”

“…Instead, it may be more appropriate to interpret these states as 3-qp excitations arising from the coupling of a g 9/2 neutron to known negative-parity states in the even-even 70 Se core [5]. Similar 3-qp structures have been found in other neighboring odd-A nuclei, including 69 Ge [25] and 71 As [26]. The analogous states in 71 Se show some similarities to and differences from the systematic patterns established in these cases, as will be discussed further below.…”

“…The lack of a second such 19 2 − state in 71 Se could point to different intrinsic configurations for the two 5 − states in 70 Se. We note also that the decays of the second, higher-lying 19 2 − state in 69 Ge were only very weakly observed [25]. In addition, we searched for a 15 .…”