Time-dependent coupled-channel calculations of positronium-formation cross sections in positron-hydrogen collisions

Abstract

We demonstrate the usefulness of the time-dependent coupled channel (TDCC) method in theoretical studies of atomic rearrangement collisions. In the TDCC method, coupled-channel partial differential equations for scattering wave functions are solved time dependently. We develop the Hankel-interpolation method, which is used to transform wave functions from an initial coordinate to a final coordinate system. By using this method, reaction cross sections of rearrangement collisions can be directly extracted from solutions of TDCC equations. We calculate positronium-formation cross sections in positron-hydrogen collisions in which a considerable number of theoretical calculations and precise experiments have been made. The present results for positron energies of 6.8--35 eV are in excellent agreement with the recent experiment of Zhou et al. [Phys. Rev. A 55, 361 (1997)].