^(248)Cf中K^(π)=2^(-)带的研究

Investigation of K^(π)=2^(-) Band in ^(248)Cf

本工作给出了对^(248)Cf中2^(-)带的理论分析。这条带在实验中被观测到自旋25h和激发能高于4 MeV,因此该原子核在相应组态下裂变位垒至少持续到此角动量和激发能。就顺排性质和衰变特征对实验2^(-)带背后的物理机制进行了探讨。二准中子,二准质子以及非轴对称八极形变(基于反射不对称壳模型)内禀结构的不同假设通过电磁跃迁性质进行评估。结果显示,实验2^(-)带的谱学特性在粒子-声子混合图像下能得到较好的解释:准粒子阻碍了向基带的跃迁,非轴对称八极声子增大了旋称伙伴带的能级劈裂,减弱了带间相互作用。该核低激发态展现的超导和正常相共存被尝试性地归因于中子152亚壳附近对相互作用的减弱。

An independent theoretical analysis is presented for the 2^(-)band in^(248)Cf,which has been identified to spin 25 h and excitation energy≥4 MeV,implying the fission barrier persists at least up to that angular momentum and excitation for the configuration.The underlying physics for the experimentally observed band is discussed in terms of alignment properties and decay pattern.Different scenarios for assumptions about intrinsic configuration are assessed with transition rates analysis.It turns out that only by invoking a particle-phonon mixing picture can the decay characteristics of the pair of bands be well accounted for,i.e.quasiparticle nature forbids decay to ground-state band,non-axial octupole phonon shifts the signature partners in energy and diminishes mutual interaction.The coexisting normal and superconducting phases are tentatively attributed to weak neutron pairing in the proximity of 152 deformed shell gap.