Photoionization cross sections of doubly excited resonances in ytterbium

Abstract

The authors report measurements of doubly excited resonances in the ground-state photoionization spectrum of ytterbium using the monochromatized synchrotron radiation from the DORIS II storage ring at HASYLAB and a thermionic diode detector. Their measurements cover the J=1' spectrum between 48000 and 80000 cm-1. It was possible to observe the doubly excited resonances at a much improved signal-to-noise ratio and the error in the cross section is estimated to be about 10%. The photoionization cross section is dominated by strongly autoionizing resonances which are interpreted as members of the doubly excited Rydberg series built on the 4f 14 5d (2D32/, 5/2) and 4f 14 6p(2P1/2, 3/2) parent ion configurations. Lifetimes, shape parameters and resonance energies of the broad overlapping resonances which belong to the (Xe)4f 14 5d6p configuration were extracted from the photoionization cross sections using a relation derived by Mies (1968).

Static Dipole Polarizability of Ytterbium

“…There are further contributions from photoionization resonances associated with inner shell transitions. Cross sections have been measured by Griesmann et al with a limited range of energies . These high-frequency transitions may be sufficient to explain the difference from our recommended polarizability of 143.…”

“…Cross sections have been measured by Griesmann et al with a limited range of energies. 55 These high-frequency transitions may be sufficient to explain the difference from our recommended polarizability of 143.…”

Autoionizing Resonances in Three-Photon Ionization Spectrum of the Ytterbium Atom

“…In this work, the spectrum of three-photon ionization of ytterbium atoms is studied in the spectral interval from 16814.4 to 18100 cm −1 containing low-located odd autoionizing levels with energies of 50443.2-54300 cm −1 [14][15][16][17][18][19][20], which can be excited by three photons. The data available at present on autoionizing levels from the indicated range were obtained within the photoabsorption method [17,20], as well as emission [19], photoionization [14], and three-stage resonance-ionization spectroscopies [15,16,18]. Their analysis demonstrates that, for a number of levels, the corresponding energies determined with the use of different schemes of their excitation are substantially different.…”

“…Their analysis demonstrates that, for a number of levels, the corresponding energies determined with the use of different schemes of their excitation are substantially different. Therefore, the determination of energies for those levels by schemes for their excitation that would be different from those used in works [14][15][16][17][18][19][20] is also challenging. Note also that at present, except for works [11,21], there are no other data concerning the three-photon ionization of ytterbium atoms in the examined spectral interval.…”

Energies, Landé Factors, and Lifetimes for Some Excited Levels of Neutral Ytterbium (Z = 70)

“…The Rydberg and autoionizing states of neutral ytterbium were also studied by Xu et al [19]. Griesmann et al presented photoionization cross-sections of doubly excited resonances in ytterbium [20]. Wu and co-workers measured some new energy levels belonging to the 4f 14 6snp 3 P 0,2 series, and investigated sixteen autoionizing levels of Yb [21,22].…”