AN L(2) CALCULATION OF POSITRON-HYDROGEN SCATTERING AT INTERMEDIATE ENERGIES

Calculations of positron-hydrogen scattering at intermediate energies up to a maximum energy of 6.0 Ryd are performed using the close-coupli ng (cc) approach. A large L(2) basis of positron-hydrogen channels (28 states) is supplemented by the Ps(1s), Ps(2s) and Ps(2p) channels. Th e inclusion of the positronium states in the cc expansion leads to a m odel which can describe most of the physics of the positron-hydrogen s ystem with a reasonable degree of accuracy. In particular, the positro nium formation cross section, the total reaction cross section and the ionization cross section are all in agreement with experiment.