相对论平均场理论对^(196)Pb超形变态的研究

Study of the Superdeformed State of ^(196)Pb in the Relativistic Mean Field Theory

在形变约束的相对论平均场理论框架下,用TMA,PK1,NL3和NL-SH相互作用对196pb的超形变态进行了系统研究．给出了196pb的位能曲线、基态和超形变态的形变以及超形变态退激的激发能． 196Pb的基态为β2≈-0．15的扁椭球,超形变激发态为β2≈0．60的长椭球,激发能在4-5MeV之间,势阱深度在1-2．2MeV之间．这些结果与最近观测的实验数据符合得非常好,表明相对论平均场理论能够较好地描述196Pb超形变转动带带首的能量．

Based on the constrained relativistic mean field （RMF） theory, the superdeformed states of ^196Pb are systematically investigated with four different interactions, TMA, PK1, NL3 and NL-SH. The potential surface, the quadruple deformation of ground and superdeformed states, and the excitation energies of superdeformed states are calculated. The results show that the shape of ^196Pb is oblate for the ground state with deformation β2 ≈ -0.15, and prolate for the superdeformed states with deformation β2 ≈ 0.60. The calculated excitation energy and the depth of the potential well of the superdeformed state are approximately equal to 4.5MeV and 1.6MeV, respectively. These results are in good agreement with the current experimental data. It indicates that RMF theory can well describe the energy of the band head of superdeformed rotational band in ^198Pb.