CALCULATION OF THE TOTAL AND TOTAL IONIZATION CROSS-SECTIONS FOR POSITRON SCATTERING ON ATOMIC-HYDROGEN

The total and total ionization cross sections for positron scattering on atomic hydrogen are calculated by applying the convergent close-coupling method to the model where positronium-formation channels are omitted. This model accurately describes the physics of the scattering whenever the positronium-formation cross section is negligible, in particular, above 100 eV for this system. The total ionization cross section results in this energy region are in excellent agreement with the recent measurements of Jones et al. [J. Phys. B 26, L483 (1993)], and so lie below the earlier measurements of Spicher et al. [Phys. Rev. Lett. 64, 1019 (1990)], and the recent calculations of Acacia et al. [Phys. Lett. (to be published)]. The total cross section is in very good agreement with the recent measurements of Zhou et al. (unpublished) down to 30 eV.