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

Abstract

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 4s ²4p ^{6 1}S₀) has been extended to the complete 4s ² 4p ⁵ 5s, 6s, 7s, 5p, 4d, 5d, 4f, 5g, and 4s 4p ⁶ 4d configurations and the nearly complete 4s ²4p ⁵ 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 4p ⁵ n g, n = 5,6 levels is 648 050 ± 60 cm⁻¹ (80.349 ± 0.007 eV).