Analysis of the Spectrum of Five-Times-Ionized Zirconium (Zr vi)

The spectrum of Zr vi has been observed in a sliding-spark discharge with a 5-m grazing-incidence spectrograph. The analysis has yielded nearly all levels of the 4p44d configuration that can combine with the 4p52P ground term. All of the 4p45s levels as given by Chaghtai were confirmed. The 4s24p44d+4s24p45s+4s4p6 level structure has been theoretically interpreted, with configuration-interaction effects included. The 4s4p6²S12 level was found to have a 24% 4s24p4(1D)4d2S character and the 4s24p4(¹D)4d²S12 level a 21% 4s4p6 2S character. The energy parameters determined from a least-squares fit to the observed level values are compared with Hartree–Fock (HF) calculations. The ionization energy is estimated to be 95.8±0.6 eV.