【摘要】 利用能量为44MeV的13C束流,通过重离子熔合蒸发反应82Se(13C,4n)91Zr布居了稳定核91Zr的高自旋态.基于γ-γ符合关系扩展了91Zr21/2+同核异能态上的能级纲图,根据实验提取的γ跃迁的角分布系数对部分能级的自旋进行了指认.前人对21/2+同核异能态下正负宇称能级已指认为质子在π(p1/2,g9/2)轨道的激发耦合价中子vd5/2;在π(f5/2,p3/2,p1/2,g9/2)和v(d5/2,s1/2,d3/2,g7/2,h11/2)空间内,经过系统性的分析和比较91Zr邻近核高自旋态能级结构,指出同核异能态上正宇称态激发机制依次为质子跨越38子壳π(f5/2,p3/2)→πp1/2激发和中子跨越50闭壳vg9/2→vd5/2激发,同核异能态上负宇称态可能涉及质子跨越38子壳π(f5/2,p3/2)→πg9/2激发与价中子vd5/2→vh11/2激发的竞争.更多还原

【Abstract】 High spin states of stable nucleus 91Zr have been studied with the 82Se(13C,4n) 91Zr fusion evaporation reaction at an incident beam energy of 44 MeV.Based on γ-γ coincidence relationships and ADO ratios,the level scheme of 91Zr above the 21/2+ isomer has been extended and the spins of partial states have been assigned.It has been shown that the low-lying levels below the 21/2+ isomer are dominated by the proton excitations within the π(p1/2,g9/2) shell model orbitals.According to systematic analysis and comparison with neighboring nuclei,the positive-parity states above the 21/2+ isomer can be understood as the proton excitations within the π(f5/2,p3/2,p1/2) shell model orbitals and one neutron excitation across the N=50 shell gap(vg9/2→vd5/2) ,the negative levels above the 21/2+ isomer might concern competition between one proton excitation across the Z=38 shell gap(π(f5/2,p3/2) →πg9/2) and the neutron excitation within(vd5/2,vh11/2) shell model orbitals.更多还原