Lanthanide luminescence is dominated by quenching by high-energy oscillators in the chemical environment. The rate of non-radiative energy transfer to a single H₂O molecule coordinated to a Eu³⁺ ion exceeds the usual rates of emission by an order of magnitude. We know these rates, but the details of these energy transfer processes are yet to be established. In this work, we study the quenching rates of [Eu(D₂O)₉]³⁺ and [Eu(DOTA)(D₂O)]⁻ in H₂O/D₂O mixtures by sequentially exchanging the deuterons with protons. Flash freezing the solutions allows us to identify species with various D/H contents in solution and thus to quantify the energy transfer processes to individual OH-oscillators. This is not possible in solution due to fast exchange in the ensembles present at room temperature. We conclude that the energy transfer processes are accurately described, predicted, and simulated using a step-wise addition of the rates of quenching by each O–H oscillator. This documents the sequential increase in the rate of the energy transfer processes in the quenching of lanthanide luminescence, and further provides a methodology to identify isotopic impurities in deuterated lanthanide systems in solution.

中文翻译：

---

[Eu(D2O)9]3+ 和 [Eu(DOTA)(D2O)]− 激发态寿命的逐步变化作为内球 O-H 振荡器数量的函数


镧系元素的发光主要是通过化学环境中高能振荡器的猝灭来实现的。非辐射能量转移到与 Eu ³⁺ 离子配位的单个 H ₂ O 分子的速率超出了通常的发射速率一个数量级。我们知道这些速率，但这些能量转移过程的细节尚未确定。在这项工作中，我们研究了 [Eu(D ₂ O) ₉ ] ³⁺ 和 [Eu(DOTA)(D ₂ 在 H ₂ O/D ₂ O 混合物中，通过顺序用质子交换氘核。快速冷冻溶液使我们能够识别溶液中具有不同 D/H 含量的物种，从而量化到各个 OH 振荡器的能量转移过程。由于室温下存在的整体的快速交换，这在解决方案中是不可能的。我们得出的结论是，通过逐步添加每个 O-H 振荡器的淬灭速率，可以准确地描述、预测和模拟能量传递过程。这记录了稀土发光猝灭过程中能量转移过程速率的连续增加，并进一步提供了一种识别溶液中氘化稀土系统中同位素杂质的方法。