POSITRON SCATTERING BY ATOMIC-HYDROGEN INCLUDING POSITRONIUM FORMATION

Positron scattering by atomic hydrogen including positronium formation has been formulated using the R-matrix method and a general computer program written. In an initial calculation, S, P, D and F partial wave cross sections have been evaluated for a coupled channel static approximation. The results presented in the energy range 0.5-4.5 Ryd are in agreement with those obtained by other workers. However a broad S-wave resonance not previously seen has been found in the positronium formation cross section at approximately 2.62 Ryd with a width of 0.31 Ryd. The mechanism for the formation of this resonance is discussed.