The infrared band strengths of H_2_O, CO and CO_2_ in laboratory simulations of astrophysical ice mixtures.
Abstract
Infrared spectroscopic observations toward objects obscured by dense cloud material show that H_2_O, CO and, likely, CO_2_ are important constituents of interstellar ice mantles. In order to accurately calculate the column densities of these molecules, it is important to have good measurements of their infrared band strengths in astrophysical ice analogs. We present the results of laboratory experiments to determine these band strengths. Improved experimental methods, relying on simultaneous independent depositions of the molecule to be studied and of the dominating ice component, have led to accuracies better than a few percent. Furthermore, the temperature behavior of the infrared band strengths of CO and H_2_O are studied. In contrast with previous work, the strengths of the CO, CO_2_, and H_2_O infrared features are found to depend only weakly on the composition of the ice matrix, and the reversible temperature dependence of the CO band is found to be weaker than previously measured for a mixture of CO in H_2_O.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- April 1995
- DOI:
- 10.48550/arXiv.astro-ph/9409076
- arXiv:
- arXiv:astro-ph/9409076
- Bibcode:
- 1995A&A...296..810G
- Keywords:
-
- INFRARED: ISM: LINES AND BANDS;
- ISM: ABUNDANCES;
- DUST;
- ISM: MOLECULES;
- MOLECULAR DATA;
- METHODS: LABORATORY;
- Astrophysics
- E-Print:
- 17 pages uuencoded compressed Postscript file-- includes all 6 figures (replaces most recent posting with only figs 2-5)