Optical lines of Xe⁹⁺ and Xe¹⁰⁺ ions measured at a low-energy electron beam ion trap.

This work reported the investigation of optical spectra of Rh-like Xe⁹⁺ and Ru-like Xe¹⁰⁺ ions at a low-energy electron beam ion trap. The line from 4d^{9 2}D_3/2 - ²D_5/2 M1 transition of Xe⁹⁺ ions was remeasured, the wavelength of which was determined to be 598.365(5) nm, and the uncertainty was significantly improved. In the region of 200 - 700 nm, four spectral lines emitted from Xe¹⁰⁺ ions were directly observed for the first time. The relativistic many-body perturbation method was adopted for the investigation of fine structure in Xe¹⁰⁺ ions. The theoretical and experimental results were in good agreement within 2%, and the four observed lines of Xe¹⁰⁺ ions were identified.