Highly resolved infrared spectra of pure CO2 ice (15–75 K)⋆
Raymond and Beverly Sackler Laboratory for Astrophysics, Leiden
Observatory, Leiden University, PO
2300 RA, Leiden, The Netherlands
2 Department of Physics and Astronomy, The University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
3 Current address: New York Center for Astrobiology, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180, USA
Received: 20 March 2013
Accepted: 14 May 2013
Context. The ν2 bending mode of pure CO2 ice around 15.2 μm exhibits a fine double-peak structure that offers a sensitive probe to study the physical and chemical properties of solid CO2 in space. Current laboratory spectra do not fully resolve the CO2 ice features.
Aims. To improve the fitting of the observed CO2 features, high-resolution solid-state infrared spectra of pure CO2 ice are recorded in the laboratory for a series of astronomically relevant temperatures and at an unprecedented level of detail.
Methods. The infrared spectra of pure CO2 ice were recorded in the 4000 to 400 cm-1 (2.5–25 μm) region at a resolution of 0.1 cm-1 using Fourier transform infrared spectroscopy.
Results. Accurate band positions and band widths (FWHM) of pure CO2 ice are presented for temperatures of 15, 30, 45, 60, and 75 K. The focus of this spectroscopic work is on the CO2 (ν2) bending mode, but more accurate data are also reported for the 12CO2 and 13CO2 (ν3) stretching mode, and CO2 (ν1+ν3) and (2ν2+ν3) combination bands.
Key words: astrochemistry / line: profiles / methods: laboratory / techniques: spectroscopic / ISM: lines and bands / ISM: molecules
FITS files of the spectra are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (220.127.116.11) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/555/A85
© ESO, 2013