The R matrix with pseudostates and convergent close-coupling methods are applied to the calculation of excitation and ionization cross sections for the simplified S-wave model of e-${\mathrm{He}}^{+}$ scattering. Very good agreement is obtained between the results of the two methods. Furthermore, the problem of Rydberg series of pseudoresonances, converging to the unphysical positive-energy states in the continuum, is shown to be almost negligible if large basis sizes or simple averaging procedures are used.

DOI:https://doi.org/10.1103/PhysRevA.55.3236