Low energy collisions between ground-state oxygen atoms

Elastic scattering cross sections have been calculated for the O(P-3) + O(P -3) collision at energies E = 1-10 eV using exact quantum calculations and the semiclassical Jeffries-Wentzel-Kramers-Brillouin approximation with the full set of 18 states of O-2 which separate to this system. These cross se ctions are required for calculating escape probability from planetary atmos pheres. In addition, an average potential has been calculated and compared to popularly used potential energy forms. The average potential has also be en used to generate the cross sections in this energy range. Escape depths for E = 1 and 10 eV have been calculated to be 1.0 x 10(15) and 2.5 x 10(14 )/cm(2), respectively. (C) 2001 Elsevier Science Ltd. All rights reserved.