The Infrared Spectrum of Magnesium (1800 < σ < 9000 cm^-1) and an Extension of the Term Systems of Mg I and Mg II

Abstract

The spectrum of neutral and singly ionized magnesium produced by a hollow-cathode discharge has been observed by the Fourier transform spectroscopy technique between 1800 and 9000 cm-1. The observations reported here have allowed an extension of the term systems of Mg I and Mg II; more particularly, first observational evidence is reported for 3s ng 1,3G(n ⩽ 8) terms of Mg I and ni 2I(n ⩽ 10) terms of Mg II. The results are also used for refining the identification of magnesium lines in the solar photospheric spectrum.

Infrared transitions and oscillator strengths of Ca and Mg

“…The majority of our lines appear in the work by Biémont & Brault (1986) except for the transitions from the 6g, 7g, and 7h states. In some cases we see only one line instead of a pair of lines observed by Biémont & Brault (1986). The other components of these multiplets was not resolved due to their low intensity and close wavenumbers (i.e.…”

“…Table 3 also shows the wavenumbers from ACE solar spectra (Hase et al 2010). The majority of our lines appear in the work by Biémont & Brault (1986) except for the transitions from the 6g, 7g, and 7h states. In some cases we see only one line instead of a pair of lines observed by Biémont & Brault (1986).…”

“…As in Table 1, each region has its own scale of arbitrary units for the emission intensity I ki . Our measured wavenumbers in Table 3 are compared with experimental wavenumbers listed in NIST Atomic Spectra Database (ASD), which reproduces the data from the laboratory measurement by Biémont & Brault (1986). Table 3 also shows the wavenumbers from ACE solar spectra (Hase et al 2010).…”

“…Using a hollow-cathode discharge technique, Biémont & Brault (1986) measured IR spectrum from 1800 to 9000 cm −1 . Their Fourier transform spectrometer (FTS) measurements gave the first laboratory observation of 3s ng 1,3 G terms of Mg i with principal quantum number n ≤ 8.…”

“…Their Fourier transform spectrometer (FTS) measurements gave the first laboratory observation of 3s ng 1,3 G terms of Mg i with principal quantum number n ≤ 8. In total, Biémont & Brault (1986) reported 116 Mg i lines with a proclaimed uncertainty not greater than 10 −3 cm −1 . Lemoine et al (1990) measured 23 Mg i lines between 740 and 1126 cm −1 with a precision of 0.0002 cm −1 using a diode-laser spectrometer.…”