Background: Response to spin-dependent operators has been investigated in the magnetic dipole and Gamow-Teller transitions, which provides magnetic properties of a nuclear system. Purpose: I investigate an isotopic dependence of the collectivity generated by the spin-dependent interactions in the Ca and Ni isotopes through the isovector (IV) spin-flip excitations. The responses in the neutral $(t_z)$ and charge-exchange $(t_{\pm})$ channels are considered in a unified way. Method: A nuclear energy-density functional approach is employed for calculating the response functions based on the Skyrme-Kohn-Sham-Bogoliubov method and the quasiparticle-random-phase approximation (QRPA). I adopt the like-particle QRPA and the proton-neutron QRPA for the neutral and charge-exchange channels, respectively. I consider the fluctuation of the proton-neutron pair fields. Results: The collective shift due to RPA correlations for the response in the neutral channel is explained by the occupation probability of neutrons in the $j_>=\ell+1/2$ orbital. Many particle-hole or two-quasiparticle excitations have a coherent contribution to form a giant resonance in neutron-rich nuclei for the charge-exchange channel. The IV spin susceptibility displays the isotopic evolution of the collectivity and the underlying shell structure. Conclusions: A repulsive character of the residual interaction in the spin-isospin channel diminishes the IV spin susceptibility due to the collectivity, while the dynamic ${}^{3}S$ pairing appearing in the charge-exchange channel opposes the reduction.
Collectivity in the light Xenon isotopes: A shell model study
在相互作用壳模型（ISM）的框架下研究了最轻的氙同位素。价空间包括位于幻闭包N=Z=50和N=Z=82之间的所有轨道。计算产生的集体变形结构的三轴性质，包括很好地已知的实验数据。对N=Z核108- 108进行了预测（仍然未知）。结果解释为正宇称轨道的伪SU（3）结构增强的四极关联与0 h 11/2轨道引入的配对关联之间的竞争。我们还研究了100-Sn核的激发对我们预测的影响。我们表明，在这个区域中的回弯是由于在0 h 11/2轨道的两个粒子的对齐。在N=Z的情况下，一个中子和一个质子对准J=11和T=0。在110- 110和112- 110中，对准开始于J=10 T=1通道，并且它主要是中子中子型。接近能带终止时，一个中子和一个质子的排列变成J=11和T=0。我们以一种更学术的态度，探讨了等矢量和等密度配对关联对108-π和110-π的结构的作用，并研究了等矢量和等密度配对凝聚在这些N~Z核中的作用。
