A Systematic Study on the Absorption Features of Interstellar Ices in Presence of Impurities
arXiv:2005.12867 · doi:10.1021/acsearthspacechem.0c00098
Abstract
Spectroscopic studies play a key role in the identification and analysis of interstellar ices and their structure. Some molecules have been identified within the interstellar ices either as pure, mixed, or even as layered structures. Absorption band features of water ice can significantly change with the presence of different types of impurities (CO, CO2, CH3OH, H2CO, etc.). In this work, we carried out a theoretical investigation to understand the behavior of water band frequency, and strength in the presence of impurities. The computational study has been supported and complemented by some infrared spectroscopy experiments aimed at verifying the effect of HCOOH, NH3 , and CH3 OH on the band profiles of pure H2O ice. Specifically, we explored the effect on the band strength of libration, bending, bulk stretching, and free-OH stretching modes. Computed band strength profiles have been compared with our new and existing experimental results, thus pointing out that vibrational modes of H2O and their intensities can change considerably in the presence of impurities at different concentrations. In most cases, the bulk stretching mode is the most affected vibration, while the bending is the least affected mode. HCOOH was found to have a strong influence on the libration, bending, and bulk stretching band profiles. In the case of NH3, the free-OH stretching band disappears when the impurity concentration becomes 50%. This work will ultimately aid a correct interpretation of future detailed spaceborne observations of interstellar ices by means of the upcoming JWST mission.
arXiv commentAccepted for Publication in the ACS Earth and Space Chemistry Journal
References in corpus (16)
- Observations of the Icy Universe
- The c2d Spitzer spectroscopy survey of ices around low-mass young stellar objects, III: CH4
- Spitzer Mid-infrared Spectroscopy of Ices Toward Extincted Background Stars
- Effects of CO2 on H2O band profiles and band strengths in mixed H2O:CO2 ices
- An Approach to Estimate the Binding energy of Interstellar Species
- Adsorption energies of carbon, nitrogen, and oxygen atoms on the low-temperature amorphous water ice: A systematic estimation from quantum chemistry calculations
- Molecular Oxygen in Oort Cloud Comet 1P/Halley
- Infrared spectroscopy of HCOOH in interstellar ice analogues
- Band profiles and band strengths in mixed H2O:CO ices
- Formation of water and methanol in star forming molecular clouds
- Composition and evolution of Interstellar Grain mantle under the effects of photo-dissociation
- IR Spectral Fingerprint of Carbon Monoxide in Interstellar Water Ice Models
- Effects of Initial Condition and Cloud Density on the Composition of the Grain Mantle
- Deuterium enrichment of the interstellar grain mantle
- CO Infrared Phonon Modes in Interstellar Ice Mixtures
- Infrared Observations of Hot Gas and Cold Ice toward the Low Mass Protostar Elias 29
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- The Cosmic-Ray Induced Sputtering Process On Icy Grains