Zhang Shuang-Quan

Pseudospin Symmetry in Relativistic Framework with Harmonic Oscillator Potential and Woods-Saxon Potential

The origin of pseudospin symmetry and its broken in real nuclei are discussed in the relativistic mean field theory. In the exact pseudospin symmetry, even the usual intruder orbits have degenerate partners. In real nuclei, pseudospin symmetry is approximate, and the partners of the usual intruder orbits will disappear. The difference is mainly due to the pseudo spin-orbit potential and the transition between them is discussed in details. The contribution of pseudospin-orbit potential for intruder orbits is quite large, compared with that for pseudospin doublets. The disappearance of the pseudospin partner for the intruder orbit can be understood from the properties of its wave function.Based on the Dirac equation, we discuss the exact pseudospin symmetry and some examples are presented. For harmonic oscillator potential there exist bound states under the condition of the exact pseudospin symmetry, V-s + V-v = 0, and even usual intruder orbits will have degenerated pseudospin partners. Apart from the harmonic oscillator potential, a Woods-Saxon potential is introduced to eliminate the redundant degeneracies due to the speciality of harmonic oscillator potential except the pseudospin degeneracy.

Giant neutron halo in exotic calcium nuclei

The properties of even-even Ca isotopes are studied using the relativistic continuum Hartree-Bogoliubov theory. The calculations reproduce very well the experimental binding energies E and two neutron separation energies S-2n. The predicted neutron drip nuclei is Ca-72. From the analysis of S-2n, the neutron radii and neutron density distribution, giant neutron haloes are predicted in Ca isotopes with A > 60.

Shell-model-like Approach (SLAP) for the Nuclear Properties in Relativistic Mean Field Theory

A Shell-model-like approach suggested to treat the pairing correlations in relativistic mean field theory is introduced, in which the occupancies thus obtained have been iterated back into the densities. The formalism and numerical techniques are given in detail. As examples, the ground state properties and low-lying excited states for Ne isotopes are studied. The results thus obtained are compared with the data available. The binding energies, the odd–even staggering, as well as the tendency for the change of the shapes in Ne isotopes are correctly reproduced.

Search for Ring-Like Nuclei under Extreme Conditions

The potential energy surfaces of 24Mg are studied within the adiabatic and diabatic constrained relativistic mean field approaches. The possible ring-like states are searched by analyzing the density distribution. It is found that in 24Mg the ring-like states are energetically favored at the extreme oblate condition |β2| ≥ 1.54 and a ring-like minimum is obtained with excitation energy Ex = 49.42 MeV and quadrupole deformation β2 = −0.93.

Coupling Parameter in the Single-j Shell Model

We propose a modified formula which is used to determine the coupling parameter.. in the Hamiltonian of the single-j shell. In comparison with the previously known formula, the new formula improves the agreement between the intruder single-j levels and the Nilsson ones. For studies of chiral bands within the particle rotor model, the new coupling parameter will considerably influence the energy splitting between the doublet bands.

Examining the Chiral Geometry in 104Rh and 106Rh

The criteria for chiral doublet bands based on one particle and one hole coupled to a triaxial rotor have been summarized. Two representative cases in A~100 odd–odd nuclei, nearly degenerate ΔI = 1 doublet bands in 104Rh and 106Rh, are checked against these chiral criteria. It is shown that 106Rh possesses better chiral geometry than 104Rh, although the energy near degeneracy is achieved in 104Rh in comparison with the constant energy separation of doublet bands in 106Rh.The criteria for chiral doublet bands based on one particle and one hole coupled to a triaxial rotor have been summarized. Two representative cases in

Analytic Continuation in the Coupling Constant Method for the Dirac Equation

A\sim100

Exotic Magnetic Rotation in (22)F

odd-odd nuclei, nearly degenerate

Band Interaction between Chiral Doublet Bands

\Delta I =1

Octupole deformation for Ba isotopes in a reflection-asymmetric relativistic mean-field approach

doublet bands in