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ABSTRACT The detection of many complex organic molecules (COMs) in interstellar space has sparked the study of their origins. While the formation of COMs detected in hot cores is attributed to photochemistry on warming grain surfaces followed by recombination of radicals and desorption, the formation routes in colder regions are still a debated issue with a number of theories such as cosmic ray bombardment on interstellar ice mantles or non-diffusive surface chemistry. Here, we present another method with reactions involving metastable atomic oxygen in the O(1D) state, which is initially produced by photodissociation of oxygen-containing species in interstellar ices. As a first example, we study the reactions of metastable oxygen atoms and methane in ices to form both formaldehyde and methanol. The reaction is studied incorporating two different surface processes: diffusive and non-diffusive chemistry. The formation of methanol and formaldehyde via metastable oxygen atoms is compared with well-known formation routes of both to understand the O(1D) contributions at different temperatures.
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Metastable insertion reactions on interstellar ices
ABSTRACT The formation of complex organic molecules (COMs) in interstellar conditions is influenced by several different processes occurring both in the gas and solid phases. Here we perform an extension of previous work to understand the influence of electronically excited metastable species on condensed phase COM formation via insertion-type reactions. These reactions involve the insertion of a chemical entity on a previously existing chemical bond. Such insertion processes involving a metastable species allow for rapid reactions with the surrounding grain ice in the absence of activation energy or diffusion barriers even under cold, dark cloud conditions. In this paper, the production of a number of interstellar species including COMs in cold dark clouds is treated both via the metastable process as well as existing suggested pathways such as radical recombination and hydrogenation of unsaturated species in order to gain insight about the relative importance of the newly added process.
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- Award ID(s):
- 1906489
- PAR ID:
- 10391718
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Monthly Notices of the Royal Astronomical Society
- Volume:
- 519
- Issue:
- 3
- ISSN:
- 0035-8711
- Format(s):
- Medium: X Size: p. 4622-4631
- Size(s):
- p. 4622-4631
- Sponsoring Org:
- National Science Foundation
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