Electronically excited NdO is a possible product of the chemistry associated with the release of Nd into the ionosphere, and emission from these states may contribute to the observations following such experiments. To better characterize the energetics and spectroscopy of NdO, we report a combined experimental and theoretical study using slow photoelectron velocity-map imaging spectroscopy of cryogenically cooled NdO⁻ anions (cryo-SEVI) supplemented by wave function-based quantum-chemical calculations. Using cryo-SEVI, we measure the electron affinity of NdO to be 1.0091(7) eV and resolve numerous transitions to low-lying electronic and vibrational states of NdO that are assigned with the aid of the electronic structure calculations. Additionally, temperature-dependent data suggest contributions from the (2)4.5 state of NdO⁻ residing 2350 cm⁻¹ above the ground anion state. Photodetachment to higher-lying excited states of NdO is also reported, which may help to clarify observations from prior release experiments.

中文翻译：

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基于 NdO 慢光电子速度图成像光谱的 NdO 电子结构---

电子激发的 NdO 可能是与 Nd 释放到电离层相关的化学产物，这些状态的发射可能有助于此类实验后的观察。为了更好地表征 NdO 的能量学和光谱学，我们报告了使用低温冷却 NdO 的慢光电子速度图成像光谱的联合实验和理论研究^-阴离子 (cryo-SEVI) 辅以基于波函数的量子化学计算。使用cryo-SEVI，我们测量NdO 的电子亲和力为1.0091(7) eV，并解决了NdO 的低电子和振动状态的许多跃迁，这些跃迁是借助电子结构计算分配的。此外，温度相关数据表明 NdO ^-的 (2)4.5 状态的贡献位于基阴离子状态上方2350 cm ^-1处。还报告了对 NdO 更高激发态的光分离，这可能有助于澄清先前释放实验的观察结果。