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[en] In sudden approximation, the probabilities of shake up and shake off processes upon ionization of atomic inner shells are calculated for outer-shell L-, M-, and N-electrons in atoms with Z=3-60. The relative role of the shake off processes increases with the atomic number. Within the same shell of the same atom, the shake off processes are relatively more probable for the nl electrons with smaller l
[en] The single K-plus multiple L- and M-shell ionization cross sections by light ions have been calculated by the semiclassical approximation. The results are compared with others calculations. The modifications of the straight-line SCA calculations for multiple ionization cross sections are discussed. (author)
[en] 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).
[en] We analyzed calculated cross sections for K-, L-, and M-shell ionization by electron impact to determine the energy ranges over which these cross sections are consistent with the Bethe equation for inner-shell ionization. Our analysis was performed with K-shell ionization cross sections for 26 elements, with L-shell ionization cross sections for seven elements, L_3-subshell ionization cross sections for Xe, and M-shell ionization cross sections for three elements. The validity (or otherwise) of the Bethe equation could be checked with Fano plots based on a linearized form of the Bethe equation. Our Fano plots, which display theoretical cross sections and available measured cross sections, reveal two linear regions as predicted by de Heer and Inokuti [in Electron Impact Ionization, edited by T. D. Märk and G. H. Dunn, (Springer-Verlag, Vienna, 1985), Chap. 7, pp. 232–276]. For each region, we made linear fits and determined values of the two element-specific Bethe parameters. We found systematic variations of these parameters with atomic number for both the low- and the high-energy linear regions of the Fano plots. We also determined the energy ranges over which the Bethe equation can be used.
[en] Generalized oscillator strengths and ionization cross sections by fast electron impact are calculated for K, L, and M shells. A nonrelativistic Hartree--Slater program is used to generate the initial states as well as the continuum wave functions. Core edge shapes and their dependence on momentum transfer are computed within this atomic model up to some tens or hundreds of eV above threshold. Some comparisons are made with experimental measurements and though details near threshold are not predicted, the gross shape of the spectrum is in quite good agreement with these data. While we confirm that the hydrogenic model is a reasonable approximation for K edges, we expect our computations to be useful in obtaining more accurate total cross sections for L and M shell excitation
[en] We discuss in the framework of linear muffin-tin orbital method and Bahcall's calculations how the ratio of L- to K-shell electron capture rates (L/K ratio) in 7Be would be affected by the host medium in which 7Be is implanted. Our calculations show that the recently observed discrepancy between the measured and observed L/K ratio in 7Be could be understood quantitatively as a result of in-medium effects distorting the L-shell electron orbital of 7Be
[en] In this study, empirical K-shell fluorescence yields (ωK) from the available experimental data for elements with 6≤Z≤99 were calculated. The experimental data are fitted using the quantity (ωK/(1-ωK))1/q (where q=3, 3.5 and 4) vs. Z to deduce the empirical fluorescence yields. A comparison is made between the results of the procedures followed here and the literature theoretical and empirical values.