Hyperspherical close-coupling method extended to the two-electron continuum region: test on the s-wave model for e-H scattering

The authors present a new numerical scheme that extends the hyperspherical close-coupling (HSCC) method to the two-electron continuum region. It is based on a matching procedure that joins the hyperspherical wavefunctions onto the asymptotic ones defined in the independent particle coordinates. They examine the scheme using a model e+H problem due to Poet that includes only states with zero angular momentum. The electron-impact cross section for the model e+H(1s) to e+H(Ns) excitation is obtained to at worst 3 significant digits for the final states with (N=2, . . ., 5) and is found stable even above the ionization threshold. A pilot calculation of ionization collision strengths is also presented for this model problem.