Studies of high-$n, 120\lesssim n\lesssim 160$, strontium $5sng, 5snh$, and $5sni$ Rydberg states are reported. Measurements using microwave spectroscopy provide the quantum defects for these states and furnish a valuable test of quantum defects reported for lower-$\ell$ states in the high-$n$ limit. With increasing $\ell$ the relativistic spin-orbit interaction becomes comparable to the electron-electron interaction resulting in the breakdown of the standard $LS$-coupling scheme. Heavier alkaline-earth quasi-two-electron systems differ significantly from a true two-electron system such as helium because indirect spin-orbit effects are dramatically enhanced. We explore the high-$n$ limit of this transition between $LS$ and $jj$ coupling. For high-$\ell$ states the quantum defects are determined predominantly by the polarizability of the inner electrons.

中文翻译：

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高ℓ锶里德堡态的量子缺陷的上限

高研究$n, 120\lesssim n\lesssim 160$, 锶 $5秒nG, 5秒nH$， 和 $5秒n\mathrm{一世}$报道了里德堡状态。使用微波光谱的测量提供了这些状态的量子缺陷，并提供了一种有价值的量子缺陷测试报告，用于较低的$\ell$ 处于高水平的州$n$限制。随着增加$\ell$ 相对论的自旋轨道相互作用变得与导致标准击穿的电子-电子相互作用相当 $升秒$-耦合方案。较重的碱土类准双电子系统与真正的双电子系统（如氦）有很大不同，因为间接自旋轨道效应显着增强。我们探索高$n$ 之间的这种过渡的限制 $升秒$ 和 $jj$耦合。对于高$\ell$ 状态量子缺陷主要由内部电子的极化率决定。