含高阶形变TRS模型的建立及其应用

Thanks to the upgrading of experimental facilities and the advance of experimental techniques, some interesting nuclear high-spin phenomena were observed, such as, collective rotational bands and high-K isomers in superheavy nuclei, rotational band with ultrahigh spin up to 65 ?, and various highly deformed bands including triaxial superdeformed band. Various theoretical models have been employed to describe these new observations, but all these calculations do not take into account the effect of high-order deformations such as β6 and β8. It has been demonstrated that these high-order deformations are important for theoretical description of nuclei with superheavy mass or large deformation. To study nuclear high-spin structure in such extreme conditions, in this project we plan to develop a TRS (Total Routhian Surface) model including high-order deformations β6 and β8, based on the present TRS model that only includes quadrupole and hexadecapole deformations. Combined with our configuration-constrained potential-energy-surface model that will be also developed to include high-order deformations, the new TRS model will be applied to calculate collective and non-collective high-spin properties of superheavy nuclei, various highly deformed nuclei and ultrahighly spinning nuclei, with focus on the effect of high-order deformations. The new model will obtain improved description of nuclear high-spin phenomena in extreme conditions and provide useful predictions for future experiments.

实验设备的升级和实验技术的进步，在原子核中不断发现有趣的高自旋观测结果，如超重核的集体转动带和高K同核异能态、自旋达到65?的超高自旋带，和三轴超形变带等各种大形变带。对于这些高自旋现象，虽然已有各种理论模型给出计算，但都没有考虑高阶形变如β6和β8的影响。而已有研究表明，高阶形变对于更准确地描述超重质量或者大形变的原子核很重要。为适应目前和以后这些极端条件下的原子核高自旋态研究，我们拟基于现有的TRS（Total Routhian Surface）模型，引入高阶形变β6和β8，建立含高阶形变的TRS模型及相应的计算程序，并用组态限制势能面模型配合，应用其研究超重核、各种大形变核、超高自旋核的集体和非集体转动性质，考察高阶形变的影响，获得对于这些核高自旋结构的更好描述，并为将来的实验提供预言。

现代实验技术的发展推动探索更加不稳定的原子核和获取更精确的观测数据，这对于理论研究也提出了相应的要求。我们成功建立并完善了含高阶形变的TRS模型和组态限制势能面模型，并应用其研究了不稳定原子核的集体转动带和多准粒子高K态以及超形变态和势能面第二极小点处的高K态。包含高阶形变beta6的模型给出改进的理论描述，更准确地重现了实验和更可信地预言理论结果。特别地，beta6是理解254No附近原子核集体转动差别的关键，也对确定超镄区高K态的能级次序有重要影响。我们主要研究了超重核区和丰中子区，对这些前沿质量区的理论工作有助于将来的实验研究。