The properties of atomic negative ions are to a large extent determined by electron-electron correlation which makes them an ideal testing ground for atomic many-body physics. In this paper, we present a detailed experimental and theoretical study of excited states in the negative ion of iridium. The ions were stored at cryogenic temperatures using the double electrostatic ion ring experiment facility at Stockholm University. Laser photodetachment was used to monitor the relaxation of three bound excited states belonging to the [Xe] $4f^{14}5d^{8}6s^2$ ionic ground configuration. Our measurements show that the first excited state has a lifetime much longer than the ion-beam storage time of $1230\pm 100\mathrm{s}$. The binding energy of this state was measured to be $1.045\pm 0.002\mathrm{eV}$. The lifetimes of the second and third excited states were experimentally determined to be $133\pm 10$ and $172\pm 35\mathrm{ms}$, respectively. Multiconfiguration Dirac-Hartree-Fock calculations were performed in order to extract binding energies and lifetimes. These calculations predict the existence of the third excited bound state that was detected experimentally. The computed lifetimes for the three excited bound states agree well with the experimental results and allow for a clear identification of the detected levels.

中文翻译：

---

激发态 inIr− 的实验和理论研究

原子负离子的性质在很大程度上取决于电子-电子相关性，这使得它们成为原子多体物理的理想试验场。在本文中，我们对铱负离子中的激发态进行了详细的实验和理论研究。使用斯德哥尔摩大学的双静电离子环实验设施将离子储存在低温下。激光光分离用于监测属于 [Xe] 的三个束缚激发态的弛豫$4F^{14}5d^{8}6{秒}^2$离子基构型。我们的测量表明，第一激发态的寿命比离子束存储时间长得多$1230\pm 100\mathrm{秒}$. 这种状态的结合能被测量为$1.045\pm 0.002\mathrm{电动汽车}$. 实验确定第二和第三激发态的寿命为$133\pm 10$ 和 $172\pm 35\mathrm{小姐}$， 分别。执行多配置 Dirac-Hartree-Fock 计算以提取结合能和寿命。这些计算预测了实验检测到的第三激发态的存在。三个激发态的计算寿命与实验结果非常吻合，并允许明确识别检测到的水平。