Laboratory spectra of CO2 vibrational modes in planetary ice analogs

• Published in: Icarus (New York, N.Y. 1962) Vol. 221; no. 2; pp. 1032 - 1042
• Main Authors: White, Douglas W., Mastrapa, Rachel M.E., Sandford, Scott A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.11.2012; Elsevier
• Subjects: Astronomy; Asymmetry; Bands; Carbon dioxide; Deposition; Earth, ocean, space; Exact sciences and technology; Experimental techniques; Ices, IR spectroscopy; Infrared; Interstellar matter; Organic chemistry; Outer solar system; Satellites, Surfaces; Solar system; Spectra; Organic chemistry; Experimental techniques; Ices, IR spectroscopy; Satellites, Surfaces; Infrared spectroscopy; Infrared absorption; Ice; High temperature; Dust grain; Absorption band; Solar system; Interstellar matter; Methanol
• ISSN: 0019-1035; 1090-2643
• DOI: 10.1016/j.icarus.2012.10.024

► CO2 IR bands are observed in H2O and CH3OH ices in temperature from 15 to 150K. ► CO2 may deposit out at higher temperatures (T>50K). ► Laboratory CO2 band positions are compared with some observational data. Laboratory spectra have shown that CO2 is a powerful diagnostic tool for analyzing infrared data from remote observations, as it has been detected on icy moons in the outer Solar System as well as dust grain surfaces in the interstellar medium (ISM). IR absorption band profiles of CO2 within ice mixtures containing H2O and CH3OH change with respect to temperature and mixture ratios. In this particular study, the ν3 CO2 asymmetric stretch mode near 4.3μm (2350cm−1), overtone mode near 1.97μm (5080cm−1), and the combination bands near 2.7μm (3700cm−1), 2.8μm (3600cm−1), and 2.02μm (4960cm−1), are systematically observed in different mixtures with H2O and CH3OH in temperature ranges from 15K to 150K. Additionally, some high-temperature deposits (T>50K) of H2O, CH3OH, and CO2 ice mixtures were performed and it was discovered that CO2 may deposit out at higher temperatures than previously recorded. These data may then be used to interpret infrared observational data obtained from icy surfaces in the outer Solar System and beyond.