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A simple modification of the Vaisburd and Evdokimov model (VE) [Russ. Phys. J. 46 , 1160 (2003)], with a acronym MVE, embodying the relativistic effects is proposed and employed to evaluate the K -shell ionization cross sections of atomic targets with atomic numbers 6 ≤ Z ≤ 92 for incident energies E Threshold ≤ E ≤ 10 GeV. For a meaningful comparison we also revisited our earlier MUIBED model [Int. J. Q. Chemistry, 108 , 1023 (2008)] to obtain the K -shell ionization cross sections for 24 atomic targets and above mention energy range. It is found that our new results from the MVE model agrees quite well not only with available experimental data but also with other theoretical values.

The differential, total, momentum transfer and viscosity cross sections for the elastic scattering of electrons and positrons by ytterbium atoms have been calculated. We have also calculated the total inelastic and ionization cross sections. In addition, the Sherman function S(θ) and the inelastic mean free paths have been determined for the scattering of both projectiles. The critical minima in the elastic differential cross sections (DCS) were determined from the analysis of the DCS and S(θ). These investigations have been carried out within the framework of two different theoretical approaches at the impact energies 1 eV–0.5 GeV for both projectiles. In the atomic domain the solution involves a complex projectile-atom optical potential while in the nuclear domain only the nuclear potential has been employed. Both approaches employ the Dirac partial wave analysis. Our results are in reasonable agreement with available experimental data and other theoretical findings. To the best of our knowledge, for positron scattering, there are no experimental data available in the literature.

Synopsis Vaisburd and Evdokimov proposed an empirical VE model to calculate the electron impact single ionization cross-sections of atoms and molecules. The extension of the modified VE model (MVE) has been proposed incorporating the relativistic effects. This model is applied to investigate the total L-shell as well as L1-, L2- and L3-subshells ionization cross-sections of various atomic targets with atomic numbers Z =1892 for incident energies up to 1 GeV. The results from the MVE model are compared with the available experimental data and theoretical findings.

The model of Cengiz (2002) [Approximate inelastic scattering cross sections of electrons. Rad. Phys. Chem. 65, 33–44] has been modified by incorporating both the ionic and relativistic corrections due to Uddin et al. (2006) [Modified Kolbensvedt model for the electron impact K-shell ionization cross-sections of atoms and ions. Eur. Phys. J. D 37, 361–369.] to investigate the electron impact s-orbital ionization in the K- and L-shells. With a single set of species independent parameters our evaluated inner shell ionization cross section of atomic targets from H to U over incident energies up to 2 GeV and of H- to Be-isoelectronic series reproduce the experimental findings nicely.

We propose an extension of our recently modified simplified-improved-binary-encounter dipole (MUIBED) model [1] suitable even for relativistic energies. This new model (XMUBED) is applied to calculate the electron impact single M-subshell ionization cross-sections for atomic targets with various charges Z (79 ≤ Z ≤ 92). The parameters of the MUIBED model for the M-shell ionization calculations are modified to account well for fourteen atomic targets (between Au and U) for the inner M-subshell ionization cross sections.

The recently proposed generalized Kolbenstvedt model (GKLV) of Haque et al (2007 Eur. Phys. J. D 42 203), for the electron impact ionization (EII) of atoms, was applied to a wide range of K-, L- and M-shell electrons of ionic targets from threshold to 1 MeV incident energy. The set of species-independent parameters, two for each of the ionized orbits, is the same as that for neutral targets, and provides an excellent account of the EII cross-sectional data for 36 ions, including those belonging to Li, Be, B, C, N, O and Ne electronic sequences as well as those having 3s-, 3p- and 3d-configurations of the M-shell in a consistent manner. The performance of GKLV is found to be better than that of the modified version of the BELL model (Haque et al 2006 Phys. Rev. A 73 052703, Haque et al 2006 Phys. Scr. 74 377).