Kristiansson Moa K, Chartkunchand Kiattichart, Eklund Gustav, Hole Odd M, Anderson Emma K, de Ruette Nathalie, Kamińska Magdalena, Punnakayathil Najeeb, Navarro-Navarrete José E, Sigurdsson Stefan, Grumer Jon, Simonsson Ansgar, Björkhage Mikael, Rosén Stefan, Reinhed Peter, Blom Mikael, Källberg Anders, Alexander John D, Cederquist Henrik, Zettergren Henning, Schmidt Henning T, Hanstorp Dag
Department of Physics, Stockholm University, Stockholm, Sweden.
Atomic, Molecular and Optical Physics Laboratory, RIKEN, Saitama, Japan.
Nat Commun. 2022 Oct 7;13(1):5906. doi: 10.1038/s41467-022-33438-y.
Negative ions are important in many areas of science and technology, e.g., in interstellar chemistry, for accelerator-based radionuclide dating, and in anti-matter research. They are unique quantum systems where electron-correlation effects govern their properties. Atomic anions are loosely bound systems, which with very few exceptions lack optically allowed transitions. This limits prospects for high-resolution spectroscopy, and related negative-ion detection methods. Here, we present a method to measure negative ion binding energies with an order of magnitude higher precision than what has been possible before. By laser-manipulation of quantum-state populations, we are able to strongly reduce the background from photodetachment of excited states using a cryogenic electrostatic ion-beam storage ring where keV ion beams can circulate for up to hours. The method is applicable to negative ions in general and here we report an electron affinity of 1.461 112 972(87) eV for O.
负离子在许多科学技术领域都很重要，例如在星际化学、基于加速器的放射性核素测年以及反物质研究中。它们是独特的量子系统，其中电子相关效应决定了它们的性质。原子阴离子是松散束缚的系统，除了极少数例外，它们缺乏光学允许的跃迁。这限制了高分辨率光谱学以及相关负离子检测方法的前景。在此，我们提出了一种测量负离子结合能的方法，其精度比以往提高了一个数量级。通过对量子态布居进行激光操控，我们能够利用低温静电离子束存储环，在其中keV离子束可以循环长达数小时，从而大幅降低激发态光剥离产生的背景。该方法一般适用于负离子，在此我们报告氧的电子亲和能为1.461 112 972(87) eV。
