Energy relaxation in superthermal collisions of carbon with oxygen: the influence of isotopic substitution

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Hauptverfasser: Bop, Cheikh T., Gacesa, Marko
Format: Preprint
Veröffentlicht: 2025
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author Bop, Cheikh T.
Gacesa, Marko
author_facet Bop, Cheikh T.
Gacesa, Marko
contents The transition from a once-dense Martian atmosphere to the thin one observed today implies a substantial loss of carbon, either through atmospheric escape or surface deposition. Accurately modeling this carbon escape necessitates accounting for collisions between energetic carbon atoms and the primary atmospheric constituents, including oxygen. To this end, we computed a highly accurate and comprehensive set of potential energy curves (PECs) for the C($^3$P) + O($^3$P) system. Based on these PECs, we derived statistically averaged total elastic and differential cross sections. Comparison with literature data for O($^3$P) + O($^3$P) collisions reveals that cross sections involving carbon can differ by up to a factor of two, indicating that oxygen is not a good proxy for modeling carbon escape. Furthermore, we evaluated the impact of all possible isotopic combinations in C($^3$P) + O($^3$P) collisions and found variations in cross sections of up to 8\%. Given the observed isotopic enrichment of carbon and oxygen in the Martian atmosphere, even such moderate differences can have a significant effect on escape models and the interpretation of planetary evolution.
format Preprint
id arxiv_https___arxiv_org_abs_2508_12807
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Energy relaxation in superthermal collisions of carbon with oxygen: the influence of isotopic substitution
Bop, Cheikh T.
Gacesa, Marko
Earth and Planetary Astrophysics
Atomic Physics
Space Physics
The transition from a once-dense Martian atmosphere to the thin one observed today implies a substantial loss of carbon, either through atmospheric escape or surface deposition. Accurately modeling this carbon escape necessitates accounting for collisions between energetic carbon atoms and the primary atmospheric constituents, including oxygen. To this end, we computed a highly accurate and comprehensive set of potential energy curves (PECs) for the C($^3$P) + O($^3$P) system. Based on these PECs, we derived statistically averaged total elastic and differential cross sections. Comparison with literature data for O($^3$P) + O($^3$P) collisions reveals that cross sections involving carbon can differ by up to a factor of two, indicating that oxygen is not a good proxy for modeling carbon escape. Furthermore, we evaluated the impact of all possible isotopic combinations in C($^3$P) + O($^3$P) collisions and found variations in cross sections of up to 8\%. Given the observed isotopic enrichment of carbon and oxygen in the Martian atmosphere, even such moderate differences can have a significant effect on escape models and the interpretation of planetary evolution.
title Energy relaxation in superthermal collisions of carbon with oxygen: the influence of isotopic substitution
topic Earth and Planetary Astrophysics
Atomic Physics
Space Physics
url https://arxiv.org/abs/2508.12807