在~（78）Ni附近集体的快速开始
Rapid onset of collectivity in the vicinity of 78Ni
摘要：
在IPN-Orsay：ALTO新建的ISOL装置上，对~（238）U光裂变产生的富中子~（84）Ga的B和B-n衰变产生的γ射线进行了研究。观察到两个活动，并将其归属于两个B衰变态：84 gGa，I =（0-）和84 mGa，I =（3-，4-）。测量了~（84）Ge的2+1和4+1激发态的激发能，E（2+1）= 624.3keV和E（4+1）= 1670.1keV。与HFB+GCM计算的比较允许建立集体性质的这个核表明一个实质性的N=50核心极化。测量了~（83）Ga中1/2+1态的激发能为247.8keV。总之，这些数据允许确认新的单粒子状态的排序后立即出现的双Z=28和N=50壳关闭，并指定78镍作为一个脆弱的，容易极化的双魔核。
英文摘要：
gamma-rays following the B and B-n decay of the very neutron rich 84Ga produced by photo-fission of 238U have been studied at the newly built ISOL facility of IPN Orsay: ALTO. Two activities were observed and assigned to two B-decaying states: 84gGa, I = (0\^-) and 84mGa, I = (3\^-, 4\^-). Excitation energies of the 2+1 and 4+1 excited states of 84Ge were measured at E(2+1) = 624.3 keV and E(4+1) = 1670.1 keV. Comparison with HFB+GCM calculations allows to establish the collective character of this nucleus indicating a substantial N=50 core polarization. The excitation energy of the 1/2+1 state in 83Ga known to carry a large part of the neutron 3s1/2 strength was measured at 247.8keV. Altogether these data allow to confirm the new single particle state ordering which appears immediately after the double Z=28 and N=50 shell closure and to designate 78Ni as a fragile and easily polarized doubly-magic core.
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