Transition energies of theDlines in Na-like ions

Abstract

The NIST electron beam ion trap (EBIT) was used to measure the D 1 (3s-3p 1/2 ) and D 2 (3s-3p 3/2 ) transitions in Na-like ions of xenon, barium, samarium, gadolinium, dysprosium, erbium, tungsten, platinum, and bismuth. The wavelengths are in the range 3-12 nm. Relativistic many-body perturbation theory calculations were carried out for the D 1 and D 2 lines for every element in the isoelectronic sequence from argon (Z = 18) to uranium (Z = 92), taking into account some higher-order terms in the quantum electrodynamics (QED) expansion. Uncertainties in the calculated values were carefully assessed by considering the uncertainties in the various contributions to the total calculated transition energies. We conclude that at the current level of accuracy, the calculated values can be taken to reliably represent the isoelectronic sequence from Z = 18 to 92. The agreement of theory and experiment for the D 1 line of bismuth (Z = 83) provides a test of QED at the level of 0.4%. Our results are also sensitive to retardation effects due to the finite speed of light and to variations in the assumed nuclear size.

Identification and Plasma Diagnostics Study of Extreme Ultraviolet Transitions in Highly Charged Yttrium

“…While elements with a high-Z atomic number have these effects amplified, ions in the medium-Z region have special importance because they allow for more accurate experiments and provide constraints to theoretical trends. In the past few years, the electron beam ion trap (EBIT) research program at the National Institute of Standards and Technology (NIST) has reported accurate measurements in the extreme ultraviolet (EUV) region that focus on systematic observations of transitions in L-shell, M-shell and N-shell ions [2][3][4][5][6][7][8][9][10][11][12][13][14]. The work reported here extends these results to a range of previously unobserved transitions of a fifth row element, yttrium.…”

“…The two most prominent ones are the well-known Na-like D 1 [7]. Gillaspy et al [7] have pointed out that the accuracy of the measurements in medium-Z to high-Z systems is sensitive to the finite nuclear size correction in the otherwise calculable QED terms. This illustrates the importance of these transitions in studies at the interface of atomic and nuclear physics.…”

“…Wavelength calibration was performed using highly charged neon lines (Ne V-VIII), xenon lines (Xe XLI-XLII), barium lines (Ba XLIII-XLIV), oxygen lines (O V-VI) and iron lines (Fe XXIII-XXIV) [5,7,11,63,64], as described in this section. Neon and carbon dioxide gases were injected into the EBIT as neutral atoms from the gas injection setup described by Fahy et al [2], with the injection pressure normally on the order of 10 −3 Pa. Iron ions were loaded from the MEVVA ion source.…”

“…Mg-like Xe XLIII lines were observed at 6.2903(6) nm and 12.9969(9) nm wavelengths, and two Na-like Xe XLIV lines were found at 6.6628(7) nm and 12.3939(7) nm. These lines are listed in the NIST Atomic Spectra Database [7,64] …”

Fully Relativistic Electron Impact Excitation Cross-Section and Polarization for Tungsten Ions

“…X-ray spectroscopy utilizing emissions from L-shell as well as M-shell tungsten ions is an attractive option for tokomak plasma diagnostics [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. The temperature of the ITER core will be sufficiently high to produce the L-shell tungsten ionic charged states.…”