Atomic Transition Probabilities of Sodium and Magnesium. A Critical Compilation

Abstract

This compilation is the first in a series of updates to a critical compilation published in 1969 [W. L. Wiese, M. W. Smith, and B. M. Miles, Atomic Transition Probabilities, Vol. II: Sodium through Calcium, NSRDS-NBS Vol. 2 (U.S. GPO, Washington, D.C., 1969)]. Atomic transition probabilities have been critically evaluated and compiled for about 11 400 spectral lines of sodium and magnesium (nuclear charge Z=11–12, respectively). The cited values and their estimated uncertainties are based on our consideration of all available theoretical and experimental literature sources. All ionization stages (except for hydrogenic) are covered, and the data are presented in separate tables for each atom and ion. Separate listings are given for “allowed” (electric dipole) transitions, on the one hand, and for “forbidden” (magnetic dipole plus electric and magnetic quadrupole) transitions, on the other. In each spectrum, lines are grouped into multiplets which are arranged in order of ascending lower and upper-level energies, respectively. For each line, the emission transition probability Aki, the line strength S, and (for allowed lines) the absorption oscillator strength fik are given, together with the spectroscopic designation, the wavelength, the statistical weights, and the energy levels of the lower and upper states. The estimated relative uncertainties of the line strength are also indicated, as are the source citations. We introduce a statistical method that we use to estimate these uncertainties for most of the cited transition rates. We only include those lines whose transition rates are deemed sufficiently accurate to qualify as reference values. Short introductions precede the tables for each ion. The general introduction contains a discussion of the principal criteria for our judgments and our method of data selection and evaluation.

IMPROVED Cr ii log(gf) VALUES AND ABUNDANCE DETERMINATIONS IN THE PHOTOSPHERES OF THE SUN AND METAL-POOR STAR HD 84937

“…These benchmark lifetimes are from very accurate theory with uncertainties ≤1%, or from other measurements made with a different technique characterized by different systematic effects and generally smaller total uncertainty. The 3.85 ns radiative lifetime of the 3 2 P 3/2 level of singly ionized Mg (National Institute of Standards and Technology (NIST) critical compilation of Kelleher & Podobedova 2008; uncertainty of ≤1% at 90% confidence level) is clearly the best benchmark for lifetime measurements around 4 ns, and it is employed here for our Cr II remeasurements. The comparison shown in Table 1 strongly supports the eight lifetime measurements by Nilsson et al (2006).…”

The elemental composition of the Sun

“…No experimental g f -values are available for our solar lines; the theoretical results of Froese-Fischer & Tachiev (2011) are the best available data (see also the latest NIST review by Kelleher & Podobedova 2008a). Sodium consists entirely of 23 Na, which has nuclear spin I = 3 2 and therefore exhibits HFS.…”

“…For Mg , we mostly adopted g f -values from the recent NIST review by Kelleher & Podobedova (2008a). These are means of two results obtained by Froese-Fisher & Tachiev (2011) using different theoretical techniques, and a third theoretical result from Siegel et al (1998).…”

MCDHF Calculations and Beam-Foil EUV Spectra of Boron-Like Sodium Ions (Na VII)

“…The latter data encompassed some long sought-for intercombination transitions so that the relative positions of doublet and quartet term systems could be established experimentally. The Sansonetti wavelength listings are complemented by transition rates mostly from a compilation by Kelleher and Podobedova [14] of computed results.…”