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

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)].