EUV photoabsorption spectra of Cd II and Cd III

The photoabsorption spectrum of singly ionized cadmium has been measured in the 23.6–110 eV region using the dual laser plasma technique. We have observed many of the 4d 10 5s → 4d 9 5s n p, m f transitions (7 ⩽ n ⩽ 9, 4 ⩽ m ⩽ 9) for the first time and identified them with the aid of Hartree–Fock and quantum defect calculations. We also report a number of window resonances in the 27–40 eV region whose origins have not been determined, and the overall shape of the 4d photoionization spectrum. Finally, we have determined four new 4d 9 nl levels of Cd 2+ .