Nonperturbative treatment of the Thomas mechanism in electron capture

Abstract
We present differential and total cross sections for charge transfer in proton-hydrogen collisions at 5, 2.8, and 1 MeV, derived from extensive nonperturbative coupled-channel calculations. We use expansions of target and projectile bound and continuum states of angular momenta up to l=2 in terms of Gaussian-type orbitals. Satisfactory convergence is reached. Good agreement is achieved with the experimental data at 5 MeV but not at 2.8 MeV.