  Application of the convergent close-coupling (CCC) method to electron-impact
ionization of the ground state of atomic hydrogen is considered at incident
energies of 15.6, 17.6, 20, 25, 27.2, 30, 54.4, 150 and 250 eV. Total through
to fully differential cross sections are presented. Following the analysis of
Stelbovics [submitted to Phys. Rev. Lett. (physics/9905020)] the equal-energy
sharing cross sections are calculated using a solely coherent combination of
total-spin-dependent ionization amplitudes, which are found to be simply a
factor of two greater than the incoherent combination suggested by Bray and
Fursa [1996 Phys. Rev. A {\bf 54}, 2991]. As a consequence, the CCC theory is
particularly suited to the equal-energy-sharing kinematical region, and is able
to obtain convergent absolute scattering amplitudes, fully ab initio. This is
consistent with the step-function hypothesis of Bray [1997 Phys. Rev. Lett.
{\bf 78}, 4721], and indicates that at equal-energy-sharing the CCC amplitudes
converge to half the step size. Comparison with experiment is satisfactory in
some cases and substantial discrepancies are identified in others. The
discrepancies are generally unpredictable and some internal inconsistencies in
the experimental data are identified. Accordingly, new (e,2e) measurements are
requested.
