Comparison of the spin-orbit selectivity of reactions involving atoms in aP-2 or P-3 state and a linear molecule in a Pi or Sigma state at very low temperature

In this work. we treat the general case of an atom in a P-2 or P-3 electron ic state reacting with a linear molecule in a (2)Pi, (2)Sigma or (3)Sigma e lectronic state. We demonstrate that the spin-orbit selectivity of the rate constant at low temperatures (T < 10 K) is associated with the different c ontributions to the long-range intermolecular potential calculated in the s pin-orbit basis set of the reactants. We give examples of applications to a few reactions of astrophysical interest. (C) 1999 Elsevier Science B.V. Al l rights reserved.