SCATTERING OF POSITRONIUM BY ATOMIC-HYDROGEN

Extensive new calculations, in the coupled-pseudostate formalism, are reported for o-Ps(1s) scattering by H(1s) in the energy range 0 to 40 eV. An S-wave resonance first predicted by Drachman and Houston [Phys. Rev. A 12, 885 (1975)] is confirmed and new resonances are found in t he P, D, F, G, and H waves. The cross section for o-Ps(ls) to p-Ps(ls) conversion is shown to have significant structure. Results for the to tal cross section and its components indicate that Ps ionization is th e main process at the higher energies. Excitation of the H atom become s increasingly important above 20 eV.