The positron-hydrogen system in a six state model

Abstract

Close coupling calculations of positron-hydrogen scattering using a six state model (H(1s, 2s, 2p), Ps(1s, 2s, 2p)) are completed for incident energies from zero to 4.0 Rydberg. The calculations are very comprehensive and all cross sections and phaseshifts for the e+-H(1s) entrance channels have been computed. The cross sections for positronium formation in the Ps(1s), Ps(2s) and Ps(2p) levels underestimate the latest experimental values. Cross sections are also computed for the Ps(1s)-p entrance channel, and these to our knowledge represent the first detailed calculation of the Ps(1s)-p scattering. Particular attention is paid to the cross sections for electron transfer since these are relevant to proposed experiments to form antihydrogen in sufficient quantities to perform spectroscopic experiments. Resonances are identified at incident positron energies both below and above the ionization threshold.