Li I spectra in the 4.65–8.33 micron range: high-Lstates and oscillator strengths

Abstract

Context. Infrared (IR) astronomy capacities have rapidly developed in recent years thanks to several ground-and space-based facilities. To take advantage of these capabilities efficiently, a large amount of atomic data (such as line wavenumber, excited-level energy values, and oscillator strengths) are needed. These data are incomplete, in particular, for lithium whose abundances are important for several astrophysical problems. Aims. No laboratory-measured spectra of Li I have been reported for wavelengths longward of 6.6 microns. We aim to find new Li I lines in the 4.65-8.33 microns range due to transitions between states with high orbital momentum (l ≥ 4) and to determine the excitation energies of these states. Methods. The Li I lines were studied using the time-resolved Fourier transform infrared spectroscopy of a plasma created by the laser ablation of a LiF target in a vacuum. The classification of the lines was performed by accounting for oscillator strengths ( f -values) calculated using quantum defect theory (QDT). The adequacy of QDT for these calculations was checked by comparison with the available experimental and theoretical results. Results. We report four new Li I lines in the 900-2200 cm -1 range that allow us to extract the excitation energies of the 6g, 6h, and 7h states of Li I, which have not been measured before. We also provide a large list of QDT-calculated f -values for Li I in the range of 1-20 microns.

Ariel – a window to the origin of life on early earth?

“…This could possibly also occur under prebiotic conditions and is considered an important step linking complex biomolecules to CH4 and NH3 [153]. The low-energy Rydberg states of atoms [154], [155], [156], [157]. generated in electric discharges are another important initiator of reactions.…”

Division B Commission 14 Working Group: Atomic Data

“…Al II (HFS): [26], Ar IX: [277], B II: [208], Br III: [140], Cl I: [300], Co II (forbidden): [256], Dy I: [292], Eu I (HFS,IS): [2,102,103,104], Fe VIII-IX: [230], Fe VIII-XVI: [37], Fe XI: [66], Fe XIII: [62], Fe XVI: [36], Fe XVII: [63], Fe XVIII: [54], Fe XVIII-XXV: [254], Gd I (IS,HFS): [145], I I: [124], K I: [51], K III: [22], La I: [106], Li I: [50], Mg VII-VIII: [177], Mn I (HFS): [25,165], Mn II : [46], N III: [112], Na I: [52], Nb I: [72,235], Nb I (HFS): [95], Nd II (HFS): [28], Ne IV : [170], Ni I: [288,291], O I: [204], O VI: [341], P II: [153], Pr I (HFS): [107,282,319], Pr II: [21], Pr II (HFS): [20], Ru I (IS,HFS): ...…”

Atomic Data: Division B / Commission 14 / Working Group Atomic Data

“…Al II (HFS): [26], Ar IX: [277], B II: [208], Br III: [140], Cl I: [300], Co II (forbidden): [256], Dy I: [292], Eu I (HFS,IS): [2,102,103,104], Fe VIII-IX: [230], Fe VIII-XVI: [37], Fe XI: [66], Fe XIII: [62], Fe XVI: [36], Fe XVII: [63], Fe XVIII: [54], Fe XVIII-XXV: [254], Gd I (IS,HFS): [145], I I: [124], K I: [51], K III: [22], La I: [106], Li I: [50], Mg VII-VIII: [177], Mn I (HFS): [25,165], Mn II : [46], N III: [112], Na I: [52], Nb I: [72,235], Nb I (HFS): [95], Nd II (HFS): [28], Ne IV : [170], Ni I: [288,291], O I: [204], O VI: [341], P II: [153], Pr I (HFS): [107,282,319], Pr II: [21], Pr II (HFS): [20], Ru I (IS,HFS): [101]…”