Laser spectroscopy of Na i quartets
TL;DR: En utilisant une decharge en impulsions avec une cathode creuse, on produit des atomes metastables dans les niveaux (2p 5 3s3p) 4 D 7/2 et (2 p 5 3 s4s) 4 S 3/2 de NaI.
Abstract: By using a pulsed hollow-cathode discharge, metastable atoms are produced in the (2${p}^{5}$3s3p)${}^{4}$${D}_{7/2}$ and (2${p}^{5}$3s3p)${}^{4}$${S}_{3/2}$ levels of Na i. A tunable laser is used to excite these atoms to levels in the 2${p}^{5}$3s3d and 2${p}^{5}$3s4s configurations, and thereby to establish a partial Grotrian diagram for the quartet system. Several possible Na i xuv laser systems are described.
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TL;DR: In this paper, energy levels, with classifications and uncertainties, have been compiled for the spectra of the neutral atom and all positive ions of sodium (Z=11) for all ionization stages of sodium.
Abstract: Energy levels, with classifications and uncertainties, have been compiled for the spectra of the neutral atom and all positive ions of sodium (Z=11). Wavelengths with classifications, intensities, and transition probabilities are also tabulated. In addition, ground states and ionization energies are listed. Where available, the hyperfine structure constants and the percentages of the leading components of the energy levels are included. For all ionization stages of sodium, at least some experimental data are available; however, for those for which only a few transitions have been measured, theoretical calculations or values obtained by isoelectronic fitting are reported. Similarly, theoretical or isoelectronically determined ionization energies are given when they are thought to be more accurate than the available experimental data would produce.
68 citations
TL;DR: In this article, the most recent experimental and theoretical studies of multiply-excited states are reviewed with emphasis on emission spectroscopy, and fine structure effects on transition wavelengths and lifetimes (autoionization) are discussed.
Abstract: Optical studies of multiply-excited states are reviewed with emphasis on emission spectroscopy. From optical measurements, properties such as excitation energies, lifetimes and autoionization widths can be determined with high accuracy, which constitutes a challenge for modern computational methods. This article mainly covers work on two-, three- and four-electron systems, but also sodium-like quartet systems. Furthermore, some comments are given on bound multiply-excited states in negative ions. Fine structure effects on transition wavelengths and lifetimes (autoionization) are discussed. In particular, the most recent experimental and theoretical studies of multiply-excited states are covered. Some remaining problems, which require further attention, are discussed in more detail.
53 citations
31 citations
TL;DR: Multiconfiguration Hartree-Fock calculations with Breit-Pauli relativistic corrections are reported for the metastable core-excited quartet states and it was found that term dependence of the radial functions was important in Na I, which tended to reduce the mixing of the different terms.
Abstract: Multiconfiguration Hartree-Fock calculations with Breit-Pauli relativistic corrections are reported for the metastable core-excited quartet states 2p/sup 5/3s3p, 2p/sup 5/3s3d, and 2p/sup 5/3s4s in Na I and Mg II, and also for 2p/sup 5/3p/sup 2/ in the latter. Both correlation and relativistic effects play an important role, as expected, but in addition it was found that term dependence of the radial functions was important. In Na I the latter tended to reduce the mixing of the different terms. Lifetime determination of the odd quartets included decay to 2p/sup 5/3s3p, 2p/sup 6/3s, and 2p/sup 6/3d levels as well as autoionization. The resulting lifetimes of several levels in Na I are in somewhat better agreement with experiment than those reported from other theories.
29 citations