Atom—Atom Collision Processes in Astrophysics: Theoretical Studies

Theoretical studies of atom-atom collision processes which may be relevant to the interpretation of astrophysical phenomena are reviewed. Work on excitation, ionization, and electron capture in atomic hydrogen by fast protons and He⁺ ions is summarized. Processes involving slow collisions that are listed include radiative charge transfer and association, associative detachment, Penning ionization, spin-change, collision-induced deactivation, mutual neutralization, and rotational excitation.