High-resolution study of oscillator strengths and predissociation rates for ¹³C¹⁸O

Michèle Eidelsberg (1) , Jean-Louis Lemaire (2) , Steven R. Federman (3) , Alan N. Heays (4) , Glenn Stark (5) , James R. Lyons (6) , Lisseth Gavilan (7) , Nelson de Oliveira (8)

1 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique
2 ISMO - Institut des Sciences Moléculaires d'Orsay
3 Department of Physics and Astronomy [Toledo]
4 Leiden Observatory [Leiden]
5 Department of Physics [Wellesley]
6 SESE - School of Earth and Space Exploration [Tempe]
7 PLANETO - LATMOS
8 Ligne DESIRS [Saint Aubin]

We carried out experiments at the SOLEIL synchrotron facility to acquire data for modelling CO photochemistry in the vacuum ultraviolet. We report oscillator strengths and predissociation rates for four vibrational bands associated with transitions from the v = 0 level of the X¹ Σ⁺ ground state to the v = 0–3 vibrational levels of the core excited W¹Π Rydberg state, and for three overlapping bands associated with the 4pπ, 5pπ, and 5pσ Rydberg states between 92.9 and 93.4 nm in ¹³C¹⁸O. These results complete those obtained in the same conditions for ¹²C¹⁶O, ¹³C¹⁶O, and ¹²C¹⁸O recently published by us, and extend the development of a comprehensive database of line positions, oscillator strengths, and linewidths of photodissociating transitions for CO isotopologues. Absorption spectra were recorded using the Vacuum UltraViolet Fourier Transform Spectrometer (VUV-FTS) installed on the Dichroïsme Et Spectroscopie par Interaction avec le Rayonnement Synchrotron (DESIRS) beamline at SOLEIL. The resolving power of the measurements, R = 300 000 to 400 000, allows the analysis of individual line strengths and widths within the bands. Gas column densities in the differentially pumped system were calibrated using the B-X (0–0) band at 115.1 nm in ¹³C¹⁸O.

Mots clés: ISM; molecular data; spectroscopy; ultraviolet

Domaines: Physique Atmosphérique et Océanique [physics.ao-ph]

Michèle Eidelsberg, Jean-Louis Lemaire, Steven R. Federman, Alan N. Heays, Glenn Stark, et al.. High-resolution study of oscillator strengths and predissociation rates for ¹³C¹⁸O. Astronomy and Astrophysics - A&A, 2017, 602, A76 (13 p.). ⟨10.1051/0004-6361/201630195⟩. ⟨insu-01562620⟩