  Excitation and charge transfer in low-energy O+H collisions is studied; it is
a problem of importance for modelling stellar spectra and obtaining accurate
oxygen abundances in late-type stars including the Sun. The collisions have
been studied theoretically using a previously presented method based on an
asymptotic two-electron linear combination of atomic orbitals (LCAO) model of
ionic-covalent interactions in the neutral atom-hydrogen-atom system, together
with the multichannel Landau-Zener model. The method has been extended to
include configurations involving excited states of hydrogen using an estimate
for the two-electron transition coupling, but this extension was found to not
lead to any remarkably high rates. Rate coefficients are calculated for
temperatures in the range 1000 - 20000 K, and charge transfer and
(de)excitation processes involving the first excited S-states, 4s.5So and
4s.3So, are found to have the highest rates.
