Electron impact ionization of beryllium isoelectronic ions

The electron impact single ionization cross-sections on the Be, B+, C2+, N3+, O4+, Ne6+, Fe22+ and U88+ atomic targets, in the beryllium isoelectronic sequence (BIS), are calculated using the modified versions of simplified improved binary-encounter dipole model (siBED) [W.M. Huo, Phys. Rev. A 64 (2001) 042719]. The modified models, QIBED (with the ionic correction) and RQIBED (with both the ionic and relativistic corrections) [M.A. Uddin, A.K.F. Haque, A.K. Basak, B.C. Saha, Phys. Rev. A 70 (2004) 032706], are found to provide an excellent description of the experimental data for all the targets in BIS with the same generic values of the two parameters d1 and d2 in the models. The RQIBED results describe satisfactorily the assessed data of Be and its predictions for U88+ account for well the experimental K-shell ionization data of Sn, with almost the same properties of the ionized orbit concerned, even up to around 2 MeV.