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

Analytic fits to the recommended electron-impact excitation and ionization cross sections for Be I are presented. The lowest 19 terms of configurations 2snl (n= 4) and 2p2 terms below the first ionization limit are considered. The fits are based on the accurate calculations with the convergent close...

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Bibliographic Details
Main Authors: Dipti, Das, T., Bartschat, K., Bray, Igor, Fursa, Dmitry, Zatsarinny, O., Ballance, C., Chung, H., Ralchenko, Y.
Format: Journal Article
Published: Elsevier 2018
Online Access:http://hdl.handle.net/20.500.11937/72848
Description
Summary:Analytic fits to the recommended electron-impact excitation and ionization cross sections for Be I are presented. The lowest 19 terms of configurations 2snl (n= 4) and 2p2 terms below the first ionization limit are considered. The fits are based on the accurate calculations with the convergent close coupling (CCC) method as well as the B-spline R-matrix (BSR) approach. The fitted cross sections provide rate coefficients that are believed to approximate the original data within 10% with very few exceptions. The oscillator strengths for the dipole-allowed transitions between all the considered states are calculated with the relativistic multi-configuration Dirac–Hartree–Fock (MCDHF) approach and compared with the CCC and BSR results. This comparison shows a very good agreement except for a handful of cases with likely strong cancellations.