Efforts to provide accurate atomic collisional data for use in fusion plasma models have been extended to provide electron-impact ionization cross sections for all stages of beryllium. Ionization cross sections are presented from the ground and first excited states of Be, ${\mathrm{Be}}^{+},$ ${\mathrm{Be}}^{2+},$ and ${\mathrm{Be}}^{3+}.$ For all cases, two perturbative distorted-wave methods are used to calculate the ionization cross section. For Be, ${\mathrm{Be}}^{+},$ and ${\mathrm{Be}}^{2+},$ the nonperturbative time-dependent close-coupling and the R matrix with pseudostates methods are used to calculate the ionization cross sections. R matrix with pseudostates calculations are also presented for ${\mathrm{Be}}^{3+}.$ In general, the two nonperturbative methods are in good agreement with each other for electron-impact ionization of Be, ${\mathrm{Be}}^{+},$ and ${\mathrm{Be}}^{2+}.$ Furthermore, for ionization from the ground and the first excited states of Be and the first excited state of ${\mathrm{Be}}^{+},$ the perturbative distorted-wave calculations are significantly higher than the nonperturbative calculations. The atomic level resolved rate coefficients generated in this work have been archived and will be used to increase the accuracy of collisional-radiative modeling for beryllium.

• Received 19 June 2003

DOI:https://doi.org/10.1103/PhysRevA.68.032712