Extreme-ultraviolet emission spectra of core-excited levels in sodium and magnesium

Abstract

Using a pulsed-hollow-cathode discharge, we have observed the emission spectra of core-excited levels of Na I and Mg II. Line identifications and implications for extreme-ultraviolet lasers are discussed.

Revised interpretation of the Na I EUV absorption spectrum

“…However, the wavelength of the 2p 6 3p 2 P • 3/2,1/2 -2p 5 ( 2 P • )3s3p( 3 P • ) 4 S 3/2 transition observed by Pedrotti et al [13] was 405.26(10) Å, which corresponds to the upper level value of 263 730(60) cm −1 . Thus, the reference to Pedrotti et al [13] in [1] was inappropriate. The value 263 773(15) cm −1 was actually given by Gaardsted and Andersen [5] in the header of their table III with a reference to Froese Fischer [10].…”

“…However, the wavelength of the 2p 6 3p 2 P°3 /2,1/2 -2p 5 ( 2 P°)3s3p( 3 P°) 4 S 3/2 transition observed by Pedrotti et al [12] was 405.26(10) Å, which corresponds to the upper level value of 263730(60) cm -1 . Thus, the reference to Pedrotti et al [12] in Ref. [1] was inappropriate.…”

“…In this table, the experimental energies of the quartet levels were derived from the observations of Holmgren et al [4], and Gaardsted and Andersen [5], while energies of the even-parity doublet levels were derived from lines observed by Sugar et al [11]. The energies of the odd-parity doublet levels were determined in this work based on the observations of Baig et al [2], except for the 2p 5 3s( 1 P • )3d 2 D • 5/2 level, which was determined from the transition to 2p 6 3d 2 D at 375.14 (10) Å observed by Pedrotti et al [13]. The position of the quartet levels relative to the ground state (and hence relative to the doublet levels) was established in the present work (see below) with an uncertainty of ±3.9 cm −1 .…”

“…The energy of the lowest quartet level, 2p 5 ( 2 P • )3s3p( 3 P • ) 4 S 3/2 , was given by Sansonetti [1] as 263 773(15) cm −1 with a reference to Pedrotti et al [13]. However, the wavelength of the 2p 6 3p 2 P • 3/2,1/2 -2p 5 ( 2 P • )3s3p( 3 P • ) 4 S 3/2 transition observed by Pedrotti et al [13] was 405.26(10) Å, which corresponds to the upper level value of 263 730(60) cm −1 . Thus, the reference to Pedrotti et al [13] in [1] was inappropriate.…”

“…To make this level optimization, we used the computer code LOPT [14]. In the list of transitions defining the level optimization problem, we assigned to each observed spectral line its measurement uncertainty quoted from the original data source [2,4,5,11,13]. For the wavelengths determined from the figures of Baig et al [2,3], the assigned uncertainty was a combination of the standard deviation of wavelengths given by Baig et al [2], which we used as reference lines, from fitted correction curves, and the measurement uncertainty specified by Baig et al for these wavelengths (±0.008 Å).…”