Institute of Physics, University of Freiburg, Hermann-Herder-Strasse 3, 79104 Freiburg, Germany.
Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, 6020 Innsbruck, Austria.
J Phys Chem A. 2023 May 25;127(20):4407-4414. doi: 10.1021/acs.jpca.3c00431. Epub 2023 May 15.
In the literature, the chemi-ionization of Li in the 2S ground level by He in a metastable state is typically described as an electron transfer process in which an electron from the 2s orbital of Li is transferred to the 1s orbital of He while an electron from the 2s orbital of He is ejected. Therefore, one would not assume that the orbital of the valence electron of He strongly influences the coupling strength of the collision complex to the ionization continuum. However, we observe that the chemi-ionization rate is decreased when He is laser-excited from the metastable 2S level to the 2P level (with = 0, 1, 2). A semiclassical treatment of the reaction dynamics reveals a strong dependence of the ionization rate on the reaction-channel-specific ionization width functions to which the observed decrease of the rate coefficients can be related to. The results are relevant for the improved understanding and control of chemi-ionization processes in merged beams and in traps.
在文献中，通常将 He 在亚稳态下将 Li 的 2S 基态中的化学离子化描述为电子转移过程，其中 Li 的 2s 轨道中的一个电子转移到 He 的 1s 轨道，而 He 的 2s 轨道中的一个电子被逐出。因此，人们不会假设 He 的价电子轨道强烈影响碰撞复合物与电离连续体的耦合强度。然而，我们观察到当 He 从亚稳态 2S 能级激光激发到 2P 能级（其中 = 0、1、2）时，化学离子化速率会降低。对反应动力学的半经典处理揭示了离子化速率对反应通道特定的离子化宽度函数的强烈依赖性，观察到的速率系数的降低可以与这些函数相关。这些结果对于改进对合并束和陷阱中化学离子化过程的理解和控制具有重要意义。
