Recommended electron-impact excitation and ionization cross sections for Be II

Abstract

An overview of the current status of electron-impact excitation and ionization cross sections for Be II is given and the recommended data sets for use in plasma modeling are presented. Accurate cross sections between the lowest 14 atomic terms of $1s^{2}nl(n\le 5)$ configurations are calculated with the convergent close-coupling (CCC) method and compared with the available experimental and theoretical results. The recommended electron-impact excitation and ionization cross sections are represented by analytical fitting functions that preserve correct asymptotic behavior. Uncertainties in the recommended data sets are determined by assessing the accuracy of the target structures, the convergence in the subsequent collisional calculations, and the fitting method. They are well within 15 % for most of the transitions. The fitting coefficients for 91 excitation cross sections and 14 ionization cross sections are provided for use in plasma modeling simulations.