标题： 低能偶极激发模式在$^{18}$O 中的反对称分子动力学 显示英文标题

标题： Low-energy dipole excitation mode in $^{18}$O with antisymmetrized molecular dynamics

摘要： 低能偶极（LED）激发在$^{18}$O 中通过在反对称分子动力学框架中使用变分方法与$K$投影的结合，以及与生成坐标方法的$\beta$约束进行了研究。 我们得到了两种 LED 状态，即具有主导壳模型结构的$1_1^-$状态和具有大$^{14}\textrm{C}+\alpha$集群成分的$1_2^-$状态。 这两种状态都具有显著的环形偶极（TD）和压缩偶极（CD）强度，表明在$^{18}$O 的 LED 激发中，TD 和 CD 模式并未分离，而是混合的。 这与像 $^{10}$Be 这类变形良好的核的 CD 和 TD 模式不同，在这种情况下，CD 和 TD 模式分别作为 $K^{\pi}=0^-$和 $K^{\pi}=1^-$激发模式在很大程度上变形的状态中产生。 显示英文摘要

摘要： Low-energy dipole (LED) excitations in $^{18}$O were investigated using a combination of the variation after $K$-projection in the framework of antisymmetrized molecular dynamics with $\beta$-constraint with the generator coordinate method. We obtained two LED states, namely, the $1_1^-$ state with a dominant shell-model structure and the $1_2^-$ state with a large $^{14}\textrm{C}+\alpha$ cluster component. Both these states had significant toroidal dipole (TD) and compressive dipole (CD) strengths, indicating that the TD and CD modes are not separated but mixed in the LED excitations of $^{18}$O. This is unlike the CD and TD modes for well-deformed nuclei such as $^{10}$Be, where the CD and TD modes are generated as $K^{\pi}=0^-$ and $K^{\pi}=1^-$ excitations, respectively, in a largely deformed state.