Mg II spectral line broadening in helium, oxygen and argon-helium plasmas

Abstract

Abstract. Stark widths (W) and shifts (d) of the astrophysically very important six (279.0777, 279.5528, 279.7998, 280.2705, 292.8633 and 293.6510 nm) singly ionized magnesium (Mg II) spectral lines in helium, oxygen and argon-helium plasmas have been measured at electron temperatures between 30 000 and 52 300 K and electron densities between 1.2 × 10 23 and 1.65 × 10 23 m −3 . They are the first experimental results obtained at electron temperatures higher than 20 000 K. A linear, low-pressure, pulsed arc has been used as an optically thin plasma source. The magnesium atoms, as impurities in the driving gases, have been introduced by erosion from the pure magnesium bands fixed on the discharge electrodes. Our measured Stark width and shift values have been compared to the existing experimental and theoretical data. We have found a good agreement with W and d values calculated by the semiclassical perturbation formalism (SCPF).

Theoretical transition probabilities, radiative lifetimes and Stark broadening parameters of singly ionized magnesium

“…Theoretical Stark broadening line widths (in pm) are displayed in the fifth column and, where appropriate, the experimental values from the literature. The final column displays the theoretical Stark line shift (a positive shift is red) and in the same way the experimental values of other authors: see Cappelle & Sahal-Bréchot (1970), Jones et al (1972), Fleurier et al (1977, Goldbach et al (1982), Bukvić et al (2004), Djeniže et al (2004), Djeniže et al (2005) and Cvejić et al (2013). Our Stark full width at half-maximum (FWHM) values are in good agreement with the experimental ones, with some exceptions.…”

“…Stark widths and shifts of six Mg II spectral lines very important in astrophysical situations (2790.77, 2795.53, 2797.99, 2802.70, 2928.63 and 2936.51 Å) have been measured by Djeniže et al (2004) with a linear low-pressure arc as a plasma source. In the same way, have measured resonance h and k spectral lines and values of the 2790.77-and 2797.99-Å lines in the 3p-3d transition.…”

Stark broadening and transition probability ratios in the Mg I spectrum

“…The tube has end-on quartz windows. The magnesium atoms were introduced through erosion of the magnesium metal bands fixed on the discharge electrodes providing conditions free of the self-absorption (Djeniže et al 2004b, and references therein; Bukvić et al 2004). The working gas was helium in flowing regime at a 532 Pa pressure.…”

Mg II 448.1 nm Spectral Line Stark Broadening Parameters

“…Magnesium atoms were introduced by eroding of the magnesium metal bands fixed on discharge electrodes providing conditions free of self-absorption. [11][12][13] The working gas used was nitrogen flowing at 133 Pa. A capacitor of 14 mF was charged up to a 40 J bank energy. The chosen conditions provide sufficient evaporation of magnesium atoms.…”