The interacting boson model with configuration mixing due to two-particle–two-hole excitations is applied to describe even-even ${}^{148-154}\mathrm{Sm}$ to investigate the cross-shell excitation effects in these nuclei. It is shown from the fitting results to the experimentally known positive-parity level energies, $B\left(E2\right)$ values, and electric quadrupole moments that the IBM configuration mixing (CM) describes these nuclei better than the IBM consistent-$Q$ formalism without the configuration mixing. Especially, the IBM-CM fitting results to the known $B\left(E2\right)$ values are significantly improved. Furthermore, it is shown from the IBM-CM fitting results that the intruder configuration turns to be always dominant in the $0_2^{+}, 2_2^{+}$, and $4_2^{+}$ states of well-deformed ${}^{150,152,154}\mathrm{Sm}$. Most notably, there is a clear normal-intruder configuration crossover along the yrast line of these nuclei described by the IBM-CM.

中文翻译：

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相互作用玻色子模型中 Even-evenSm148−154 中的构型混合

由于双粒子-双孔激发而具有构型混合的相互作用玻色子模型被应用于描述偶偶${}^{148-154}钐$研究这些原子核中的跨壳层激发效应。由实验已知的正宇称能级能量的拟合结果可知，$乙（乙2）$IBM 配置混合 (CM) 比 IBM 一致性模型更好地描述了这些原子核的值和电四极矩$问$没有配置混合的形式主义。特别是，IBM-CM 拟合结果为已知$乙（乙2）$数值显着提高。此外，IBM-CM拟合结果表明，入侵者配置在模型中始终占主导地位。$0_2^{+}, 2_2^{+}$， 和$4_2^{+}$良好变形状态${}^{150,152,154}钐$。最值得注意的是，沿着 IBM-CM 描述的这些原子核的 yrast 线，存在明显的正常入侵者构型交叉。