High-resolution emission spectra of MgH and MgD in the 600 to 850 nm wavelength region

Abstract

The emission spectra from a magnesium dc arc in hydrogen or deuterium have been photographed at high resolution from 600 to 850 nm. Thirteen new bands of MgH and 18 of MgD in the B′2Σ+–X2Σ+ system have been identified and complete rotational analyses have been performed. Term values have been obtained for all bound ground state rotational levels of MgH for ν = 4–9 and MgD for ν = 6–13 and limiting curves of dissociation have been used to determine the dissociation energy of MgH. The experimental value, D00″(MgH) = 1.27 ± 0.03 eV is in excellent agreement with theory. The ground state RKR potential curve and Franck–Condon factors for the B′–X system are reported. Data on the isotopic molecules 25MgH, 26MgH, 25MgD, and 26MgD have also been obtained.

The Molecular Line Opacity of MgH in Cool Stellar Atmospheres

“…Details about this procedure are given in a separate publication for the B ′ ← X electronic transition in MgH (Skory et al 2002). In this way, the dissociation energies D 0 0 coincide with the experimental values given by Balfour & Lindgren (1978) for the ground state and by Balfour & Cartwright (1976) for the A 2 Π state. The dissociation energies adopted here are 10,243.26 and and 12,903.71 cm −1 for the X 2 Σ + and A 2 Π of 24 MgH, respectively.…”

“…The spectrum of MgH has been extensively studied in the laboratory for many decades (Balfour & Cartwright 1976;Balfour & Lindgren 1978;Bernath et al 1985;Wallace et al 1999, and references therein) and has received some theoretical attention (Saxon et al 1978;Kirby et al 1979, and references therein). However, modern stellar atmosphere calculations require extensive, and complete, molecular line lists as molecular band absorption is the primary source of line-blanketing in cool stellar atmospheres, particularly M dwarfs.…”

Magnesium Isotopes in Metal-poor Dwarfs: The Rise of AGB Stars and the Formation Timescale of the Galactic Halo

“…The energy levels were calculated using molecular constants by Shayesteh et al (2004) and we adopted a dissociation energy of 1.27 eV (Balfour & Lindgren 1978). Oscillator strengths were obtained from transition probabilities given by Weck et al (2003).…”

Fourier transform infrared emission spectra of MgH and MgD

“…This comprehensive analysis led to an experimental value of 1.27͑3͒ eV for the dissociation energy of the X 2 ⌺ ϩ ground state of MgH. 15 Parallel to the experimental work in 1970s, several ab initio calculations were performed for the ground state and the low-lying excited states. 16 -21 A nearly complete set of laboratory references to work prior to 1977 was compiled by Huber and Herzberg.…”