Volume 566, June 2014
|Number of page(s)||15|
|Section||Atomic, molecular, and nuclear data|
|Published online||20 June 2014|
High-resolution study of oscillator strengths and predissociation rates for 13C16O and 12C18O
W – X bands and Rydberg complexes in the 92.5–97.5 nm range
1 Observatoire de Paris, LERMA, UMR 8112 du CNRS, 92195 Meudon, France
e-mail: firstname.lastname@example.org; email@example.com, firstname.lastname@example.org
2 Department of Physics and Astronomy. University of Toledo, Toledo, OH, USA
3 Department of Physics, Wellesley College, Wellesley, MA, USA
4 Leiden Observatory & Leiden University, PO Box 9513, 2300RA Leiden, The Netherlands
5 School of Earth and Space Exploration, Arizona State University, USA
6 93 Pleasant Street, Watertown MA 02472, USA
7 DESIRS beam line, Synchrotron SOLEIL, 91192 Gif-sur-Yvette Cedex Saint Aubin, France
e-mail: email@example.com, firstname.lastname@example.org
Received: 17 January 2014
Accepted: 19 March 2014
Models of astronomical environments containing CO require accurate molecular data to reproduce and interpret observations. We conduct experiments at the SOLEIL synchrotron facility to acquire data to model CO photochemistry in the vacuum ultraviolet. The improvement in UV spectroscopic instrumentation in both sensitivity and resolution provides more accurate laboratory spectroscopic determinations. We continue our work on photoabsorption oscillator strengths and predissociation rates for 12C16O; we report new measurements for two additional isotopologues, 13C16O and 12C18O, of four bands from X 1Σ+ (v′′ = 0) to the v′ = 0–3 vibrational levels of the core-excited W 1Π Rydberg state and for four overlapping bands (three resolved and one diffuse) between 92.97 and 93.35 nm. Some of the latter include unidentified perturbations. Absorption spectra were recorded using the vacuum-ultraviolet Fourier-transform spectrometer that is installed on the DESIRS beamline at SOLEIL which provides a resolving power R = 350 000. This resolution allows the analysis of individual line strengths and widths in the electronic transitions and the identification of a previously unobserved perturbation in the W(1) level. Gas column densities in the differentially-pumped system were calibrated using the B 1Σ+ – X 1Σ+ (v′ = 0,v′′ = 0) band. Absorption bands are analyzed by synthesizing line and band profiles and fitting them to the measured spectra. These considerably improved results are compared with earlier determinations.
Key words: ISM: molecules / methods: laboratory: molecular / techniques: spectroscopic / ultraviolet: ISM
© ESO, 2014
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