Impact Ionization in the Proton-H-Atom System. II. Electronic States and Transition Elements

Abstract

Paper I of this series describes the calculation of the direct impact ionization cross section ${\ensuremath{\sigma}}_{I}(\ensuremath{\epsilon})$ for low-energy proton-hydrogen-atom collisions, where an adiabatic description is essentially correct for the initial channel. To calculate this cross section it is necessary to compute Born-Oppenheimer continuum wave functions and evaluate the matrix elements of the transition operators connecting them to the ground-state components. Such electronic calculations and matrix elements are presented in this paper. The transition matrix elements are quite sensitive to the form chosen for the "electron translation factor." Present calculations have removed most of the large error appearing in perturbed stationary states (pss) theory due to neglect of this factor. The computed transition elements presented in this paper should lead to values for ${\ensuremath{\sigma}}_{I}(\ensuremath{\epsilon})$ accurate to perhaps 30%; estimated remaining error is due to spurious long-range effects which can be removed by improvement of the translation factor. Further computation making such improvements is in progress.