Eur. Phys. J. D (2016) 70: 11
https://doi.org/10.1140/epjd/e2015-60583-7

Regular Article

Electron impact ionization cross sections of beryllium-tungsten clusters^*,**

¹ Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, 84248 Bratislava, Slovakia
² Institute of Ion Physics and Applied Physics, University of Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria

^a e-mail: jan.urban@fmph.uniba.sk

Received: 15 October 2015
Received in final form: 20 November 2015
Published online: 19 January 2016

Abstract

We report calculated electron impact ionization cross sections (EICSs) of beryllium-tungsten clusters, Be_nW with n = 1,...,12, from the ionization threshold to 10 keV using the Deutsch-Märk (DM) and the binary-encounter-Bethe (BEB) formalisms. The positions of the maxima of DM and BEB cross sections are mostly close to each other. The DM cross sections are more sensitive with respect to the cluster size. For the clusters smaller than Be₄W they yield smaller cross sections than BEB and vice versa larger cross sections than BEB for clusters larger than Be₆W. The maximum cross section values for the singlet-spin groundstate clusters range from 7.0 × 10^-16 cm² at 28 eV (BeW) to 54.2 × 10^-16 cm² at 43 eV (Be₁₂W) for the DM cross sections and from 13.5 × 10^-16 cm² at 43 eV (BeW) to 38.9 × 10^-16 cm² at 43 eV (Be₁₂W) for the BEB cross sections. Differences of the EICSs in different isomers and between singlet and triplet states are also explored. Both the DM and BEB cross sections could be fitted perfectly to a simple expression used in modeling and simulation codes in the framework of nuclear fusion research.