AI 中文总结
本研究在低主量子数的铷超长程里德堡分子中观测到$\Pi$-对称电子态，通过多重态结构确认其特性，发现结合能的标度关系，并验证了格林函数计算的适用性及低n下费米赝势的失效。
AI 中文摘要
我们在$^{87}$Rb$(nP_{3/2})$+$^{87}$Rb($5S_{1/2}$)超长程里德堡分子的光谱中观测到弱束缚的$\Pi$-对称电子态。我们在主量子数$13\le n \le 16$的里德堡态中检测到这些分子。其$\Pi$态特性通过观测到的多重态结构得以明确识别：基态铷原子的$2F+1$个磁子能级因里德堡电子与价电子之间的自旋-自旋耦合发生分裂，类似于塞曼效应。我们发现分子结合能随$(n-μ_{P_{3/2}})^{-11}$快速下降，其中$μ_{P_{3/2}}$为量子亏损，表明低$n$区的里德堡态非常适合$\Pi$-对称分子的研究。我们的观测结果与基于格林函数的计算在$14\le n\le 16$范围内吻合良好，$n=13$时吻合度较差，暗示低$n$下费米赝势方法开始失效。
英文摘要
We observe weakly-bound $Π$-symmetry electronic states in the spectroscopy of $^{87}$Rb$(nP_{3/2})$+$^{87}$Rb($5S_{1/2}$) ultralong-range Rydberg molecules. We detect these molecules in Rydberg states having principal quantum number $13\le n \le 16$. Their $Π$-state character is unambiguously identified via their observed multiplet structure: the $2F+1$ magnetic sublevels of the ground-state rubidium atom separate, as in the Zeeman effect, because of the spin-spin coupling between the Rydberg and valence electrons. We find a rapid decrease in the molecular binding energy $\propto (n-μ_{P_{3/2}})^{-11}$, where $μ_{P_{3/2}}$ is the quantum defect, indicating that the low-$n$ regime of Rydberg states is ideally suited for studies of $Π$-symmetry molecules. Our observations are in good agreement with Green's function-based calculations for $14\le n\le 16$, with poorer agreement for $n=13$ hinting at the beginning of a breakdown of the Fermi pseudopotential approach at low $n$.
