O(3P) + CO2scattering cross-sections at superthermal collision energies for planetary aeronomy

Marko Gacesa, R. J. Lillis, K. J. Zahnle

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


We report new elastic and inelastic cross-sections for O(3P) + CO2 scattering at collision energies from 0.03 to 5 eV, of major importance to O escape from Mars, Venus, and CO2-rich atmospheres. The cross-sections were calculated from first principles using three newly constructed ab initio potential energy surfaces correlating to the lowest energy asymptote of the complex. The surfaces were restricted to a planar geometry with the CO2 molecule assumed to be in linear configuration fixed at equilibrium. Quantum-mechanical coupled-channel formalism with a large basis set was used to compute state-To-state integral and differential cross-sections for elastic and inelastic O(3P) + CO2 scattering between all pairs of rotational states of CO2 molecule. The elastic cross-sections are 35 per cent lower at 0.5 eV and more than 50 per cent lower at 4 + eV than values commonly used in studies of processes in upper and middle planetary atmospheres of Mars, Earth, Venus, and CO2-rich planets. Momentum transfer cross-sections, of interest for energy transport, were found to be proportionally lower than predicted by mass scaling.

Original languageBritish English
Pages (from-to)5650-5659
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - 1 Feb 2020


  • molecular processes
  • planetary nebulae: general
  • planets and satellites: Atmospheres
  • scattering


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