S-wave model for H-like ions

We present convergent close-coupling calculations of electron scattering on H-like ions within the framework of the $S$-wave model. The onset of $Z^4$ scaling is demonstrated. In addition, elimination of pseudoresonances in the singlet channel is studied via variation of the exponential parameter in the Laguerre basis. The absence of pseudoresonances in the triplet channel is explained by reference to single-differential ionization cross sections. These considerations have application to recently developed $R$-matrix with pseudostates techniques.