A quantum-mechanical investigation of O(P-3) + CO scattering cross sections at superthermal collision energies

The kinetics and energetic relaxation associated with collisions between fast and thermal atoms are of fundamental interest for escape and therefore also for the evolution of the Mars atmosphere. The total and differential cross sections of fast O(P-3) atom collisions with CO have been calculated from quantum mechanical calculations. The cross sections are computed at collision energies from 0.4 to 5 eV in the centre-of-mass frame relevant to the planetary science and astrophysics. All the three potential energy surfaces ((3)A ', (3)A '', and 2 (3)A '' symmetry) of O(P-3) + CO collisions separating to the atomic ground state have been included in calculations of cross sections. The cross sections are computed for all three isotopes of energetic O(P-3) atoms collisions with CO. The isotope dependence of the cross sections are compared. Our newly calculated data on the energy relaxation of O atoms and their isotopes with CO molecules will be very useful to improve the modelling of escape and energy transfer processes in the Mars' upper atmosphere.