2020/01/16 by Yuzhu Lu, Jing Zhao, Rulin Tang +2 · 2 citations
Physics and Astronomy · Chemistry · #Advanced Chemical Physics Studies #Radioactive element chemistry and processing #Mass Spectrometry Techniques and Applications
paper · doi:10.1063/1.5134535
openalex publication_date 2020/01/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The latest electron affinity value of an iridium atom is 1.564 36(15) eV, determined via a method based on the Wigner threshold law by Bilodeau and co-workers. However, they observed a significant deviation from the Wigner threshold law in the threshold photodetachment experiment. To address this dilemma, we conducted high-resolution photoelectron spectroscopy of Ir− via the slow-electron velocity-map imaging method in combination with an ion trap. The electron affinity of Ir was measured to be 12 614.97(9) cm−1 or 1.564 057(11) eV. We find that the Wigner threshold law is still valid for the threshold photodetachment of Ir− through a p-wave fitting of the photodetachment channel Ir−5d86s23F4→Ir5d86sb4F9/2. The photoelectron angular distributions of photodetachment channels Ir−5d86s23F4→Ir5d76s2a4F9/2 and Ir−5d86s23F4→Ir5d86sb4F9/2 were also investigated. The behavior of anisotropy parameter β indicates a strong interaction between the two channels. Moreover, the energy level 3P2 of Ir−, which was not observed in the previous works, was experimentally determined to be 4163.24(16) cm−1 above the ground state.