超Fm原子核转动谱的系统研究
Systematic Investigation on Spectroscopy of Transfermium Nuclei
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摘要: 简要介绍超Fm 原子核谱学的实验和理论研究进展，并综述本研究组近期在超Fm 原子核谱学方面的一些理论研究工作，包括：利用转动谱公式系统研究了超Fm 核区偶偶核与奇A 核的转动。结果表明，在二参数公式中，相较于AB 公式和Harris 公式， ab 公式能够更好地描述偶偶核基态转动带；通过拟合超Fm 核区奇A 核的单粒子能级，提出了一组轨道角动量依赖的Nilsson 新参数；利用粒子数守恒方法处理对关联，基于推转壳模型，系统研究了超Fm 原子核转动谱，计算得到的转动惯量、角动量顺排等与实验符合；通过分析费米面附近Nilsson 能级的占据几率以及各条轨道对角动量顺排的贡献，解释了这个质量区原子核的转动带产生回弯(上弯) 的原因。进一步，利用这组新Nilsson 参数，研究了超重核的单粒子能级结构以及微观壳修正能量。计算表明，这组新Nilsson 参数预言的超重岛中心为Z = 120 和N = 182。Experimental and theoretical studies on the spectroscopy of the transfermium nuclei are briefly reviewed.Recent theoretical progresses made by us is introduced. Moreover, the structure of the superheavy nuclei is investigated.
The rotational spectra in even-even and odd-A nuclei in this mass region are systematically studied by using several empirical formulas. Our result shows that compared with the AB formula and the Harris formula, the ab formula can give
a better description for rotational spectra of ground-state bands in even-even nuclei in this mass region. By fitting the experimental single-particle spectra of the odd-A nuclei in this mass region, a new set of Nilsson parameters is proposed.The rotational bands of the transfermium nuclei are investigated systematically by using a cranked shell model with the pairing correlations treated by a particle number conserving method. The experimental kinematic moments of inertia and angular momentum alignments are reproduced quite well. By analyzing the occupation probability of each cranked Nilsson orbital near the Fermi surface and the contributions of valence orbitals in each major shell to the angular momentum alignment, the upbending mechanism in this mass region could be understood clearly. This new Nilsson parameter set is also used to investigate the shell effects and the microscopic shell correction energies of the superheavy nuclei. The calculated results predict that center of the superheavy island is Z = 120, N = 182.Abstract: Experimental and theoretical studies on the spectroscopy of the transfermium nuclei are briefly reviewed.Recent theoretical progresses made by us is introduced. Moreover, the structure of the superheavy nuclei is investigated.
The rotational spectra in even-even and odd-A nuclei in this mass region are systematically studied by using several empirical formulas. Our result shows that compared with the AB formula and the Harris formula, the ab formula can give
a better description for rotational spectra of ground-state bands in even-even nuclei in this mass region. By fitting the experimental single-particle spectra of the odd-A nuclei in this mass region, a new set of Nilsson parameters is proposed.The rotational bands of the transfermium nuclei are investigated systematically by using a cranked shell model with the pairing correlations treated by a particle number conserving method. The experimental kinematic moments of inertia and angular momentum alignments are reproduced quite well. By analyzing the occupation probability of each cranked Nilsson orbital near the Fermi surface and the contributions of valence orbitals in each major shell to the angular momentum alignment, the upbending mechanism in this mass region could be understood clearly. This new Nilsson parameter set is also used to investigate the shell effects and the microscopic shell correction energies of the superheavy nuclei. The calculated results predict that center of the superheavy island is Z = 120, N = 182.
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