Abstract

The spectrum of the five-times-ionized yttrium atom (Y vi), excited in a sliding-spark discharge, was studied in the 160–2500-Å range. About 900 Y vi lines were classified as transitions between 101 odd and 69 even energy levels. The energy-level system established includes almost all levels of the 4s²4p⁴, 4s4p⁵, 4s²4p³4d, 5d, 5s, 6s, and 5p configurations and a number of levels of the 7s, 4f, and 4s4p⁴4d configurations. The observed level system has been theoretically interpreted by means of Hartree–Fock calculations and least-squares parametric fits. Strong configuration mixings are found between the 4s4p⁵ and 4s²4p³4d configurations, between the 4s²4p³5p and 4s4p⁴4d configurations, and between the 4s²4p³4f and 4s4p⁴4d configurations. From the optimized energy-level values, a system of Ritz-type wavelength standards with accuracies varying from 0.0003 to 0.003 Å in the range 179–500 Å has been determined. The ionization energy as determined from 4s²4p³ns levels (n = 5 − 7) is 737 110 ± 200 cm⁻¹ (91.390 ± 0.025 eV).

© 1986 Optical Society of America

Spectrum and energy levels of triply ionized yttrium (Y iv)

Gabriel L. Epstein and Joseph Reader
J. Opt. Soc. Am. 72(4) 476-492 (1982)

Spectrum and energy levels of five-times-ionized niobium (Nb vi)

Jan Olof Ekberg and Joseph Reader
J. Opt. Soc. Am. B 11(3) 415-427 (1994)

Spectrum and energy levels of six-times-ionized molybdenum (Mo vii)

Joseph Reader and Uri Feldman
J. Opt. Soc. Am. B 7(3) 253-265 (1990)

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

Joseph Reader and Nicolo Acquista
J. Opt. Soc. Am. 69(2) 239-253 (1979)

Spectrum of doubly ionized yttrium (Y iii)

Gabriel L. Epstein and Joseph Reader
J. Opt. Soc. Am. 65(3) 310-314 (1975)