Time-dependent and time-independent close-coupling methods for the electron-impact ionization of Be^{+}

The electron-impact ionization cross section of ${\mathrm{Be}}^{+}$ is calculated using both a time-dependent and a time-independent close-coupling method. The time-dependent method is based on the propagation of wave packets constructed using excited-state orbitals calculated in a core pseudopotential. The time-independent method is an $R-$matrix solution based on a total wave function constructed using antisymmetrized products of Laguerre pseudo-orbitals and zero-derivative box orbitals. In both methods, low partial-wave close-coupling results are added to high partial-wave distorted-wave results to yield ionization cross sections for ${\mathrm{Be}}^{+}$ substantially below the experimental crossed-beam measurements of Falk and Dunn [Phys. Rev. A 27, 754 (1983)] and in agreement with the recent time-independent close-coupling calculations of Bartschat and Bray [J. Phys. B 30, L109 (1997)].