Spectrum and energy levels of four-times ionized zirconium (Zr v)

The spectrum of zirconium was observed in the region from 200 to 2670 Å with a sliding-spark discharge on the 10.7-m normal-and grazing-incidence spectrographs at NBS. About 580 lines were assigned to Zr v. From these observations the energy level system of Zr v (Kr i isoelectronic sequence, ground state 4s24p6 1S0) has been extended to the complete 4s2 4p5 5s, 6s, 7s, 5p, 4d, 5d, 4f, 5g, and 4s 4p6 4d configurations and the nearly complete 4s24p5 6d and 6g configurations. About 330 lines have been classified. All observed configurations have been theoretically interpreted. The energy parameters determined by least-squares fits to the observed levels are compared with Hartree-Fock calculations. The ionization energy derived from the 4p5n g, n = 5,6 levels is 648 050 ± 60 cm−1 (80.349 ± 0.007 eV).