The crystal structure and electronic spectra of the T_h symmetry hexanitritoytterbate(III) anion have been studied in Cs₂NaY_0.96Yb_0.04(NO₂)₆, which crystallizes in the cubic space group Fm3̅. The emission from Yb³⁺ can be excited via the NO₂^– antenna. The latter electronic transition is situated at more than twice the energy of the former, but at room temperature, one photon absorbed at 470 nm in the triplet state produces no more than one photon emitted. Some degree of quantum cutting is observed at 298 K under 420 nm excitation into the singlet state and at 25 K using excitation into either state. The quantum efficiency is ∼10% at 25 K. The energy level scheme of Yb³⁺ has been deduced from excitation and emission spectra and calculated by crystal field theory. New improved energy level calculations are also reported for the Cs₂NaLn(NO₂)₆ (Ln = Pr, Eu, Tb) series using the f-Spectra package. The neat crystal Cs₂NaYb(NO₂)₆ has also been studied, but results were unsatisfactory due to sample decomposition, and this chemical instability makes it unsuitable for applications.

中文翻译：

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Cs ₂ NaYb（NO ₂）_6的电子光谱：有量子切割吗？

在对称空间群Fm 3中结晶的Cs ₂ NaY _0.96 Yb _0.04（NO ₂）_6中研究了T _h对称六氮杂异氰酸酯（III）阴离子的晶体结构和电子光谱。Yb ³⁺的发射可以通过NO ₂激发^–天线。后一种电子跃迁的能量是前者的两倍，但在室温下，在三重态下在470 nm处吸收的一个光子产生的光子发射不超过一个。在420 nm激发下于298 K激发到单重态，在25 K激发下进入任一态，观察到一定程度的量子切割。在25 K时，量子效率约为10％。Yb ^3+的能级方案已从激发和发射光谱中推导得出，并通过晶体场理论计算得出。还报告了使用f - Spectra软件包对Cs ₂ NaLn（NO ₂）₆（Ln = Pr，Eu，Tb）系列进行的新的改进的能级计算。整洁的水晶Cs还研究了₂ NaYb（NO ₂）₆，但由于样品分解而导致结果不理想，并且这种化学不稳定性使其不适用于应用。