超重核转动性质的研究

In the past decades, the properties of the superheavy nuclei have always been one of the most important problems in nuclear structure research. Recent years, due to the development of the experimental technique, more and more rotational spectra for the nuclei with proton number Z≥100 have been observed. To learn more about the shell structure of the nuclei around the island of stability, an indirect way is to study the spectroscopy of these lighter transfermium and superheavy nuclei. Up to now, rotational properties of the transfermium and superheavy nuclei have become one of the most important issues in the nuclear structure study. Pairing correlations are crucial for the investigation of the rotating nuclei, e.g., for the rotational states, the theoretical calculations give much larger moment of inertia than the experimental data when the pairing is neglected. Particle number conserving method is a good method for treating the pairing correlations. In the framework of covariant density functional theory, this project will develop a fully self-consistent particle number conserving method based on cranking relativistic mean field theory. This project will investigate the involution of the moment of inertia, potential energy surface and the single particle levels with cranking frequency, and investigate the rotational properties and the angular momentum alignment mechanism for the superheavy nuclei systematically. This investigation will improve not only our understanding of the pairing correlations and shell structure of the superheavy nuclei, but also the reliability of the theoretical description. This investigation will provide important microscopic basis for the further experimental study as well.

过去数十年中，超重核的性质一直是核结构研究中的重要问题。近年来，由于实验技术的发展，观测到了越来越多的质子数Z≥100 核素的转动谱。通过研究这些超镄核与超重核的谱学性质，我们可以间接地获取超重岛附近原子核壳结构的信息，这对研究超重核的稳定性及超重岛的位置至关重要。目前，超镄核与超重核的转动已成为原子核结构研究中最重要的前沿热点问题之一。对关联在研究原子核转动时非常重要，例如，对于原子核的转动激发态，忽略对关联效应的理论计算给出比实验值大很多的转动惯量。粒子数守恒方法能够很好地处理对关联。本项目拟在协变密度泛函框架下，发展完全自洽的基于推转相对论平均场理论的粒子数守恒方法。本项目将分析超重核的转动惯量、势能曲面及单粒子能级随推转频率的演化，系统研究超重核的转动性质及角动量顺排机制。此研究将有助于加深对超重核对关联与壳结构的理解，改进理论描述的可靠性，并为相关实验研究提供重要的微观依据。

上世纪六十年代，理论核物理学家预言了在质子数Z=114，中子数N=184处存在一个超重岛，自此以后，探索原子核的质量和电荷上限，研究超重核的性质一直是核结构研究中的重要问题。近年来，由于实验技术的发展，观测到了越来越多的质子数Z=100 附近核素的转动谱。通过研究这些原子核的谱学性质，我们可以间接地获取超重岛附近原子核壳结构的信息。目前，超镄核与超重核的转动性质已成为原子核结构研究中最重要的前沿热点问题之一。本项目在协变密度泛函理论框架下，发展了完全自洽的基于推转相对论平均场的类壳模型方法（也称作粒子数守恒方法），从而能够统一、自洽地处理原子核的形变、转动以及对关联。此研究有助于加深对原子核对关联与转动模式的理解，改进理论描述的可靠性，并为相关实验研究提供重要的微观依据。项目开展过程中，采用粒子数守恒方法，系统研究了反磁转动中对关联的效应、稀土区原子核高K同核异能态的性质、质子发射核的转动性质等问题。由于计算的耗时性，采用新发展的基于推转协变密度泛函理论的类壳模型方法，目前对轻核60Fe的转动带进行了研究。项目执行期间，在《Physical Review C》、《Nuclear Physics A》等期刊上共发表相关SCI文章9篇，核心期刊文章1篇，其中第一作者文章7篇。