Electron-impact broadening parameters for Be II, Sr II, and Ba II spectral lines

¹ Data Center for High Energy Density Physics, Institute of Applied Physics and Computational Mathematics, 100088 Beijing, PR China
e-mail: alexduan1967@hotmail.com
² National Astronomical Observatories, Chinese Academy of Sciences, 100012 Beijing, PR China
³ Pakistan Atomic Energy Commission, PO Box 1114, 44000 Islamabad, Pakistan
⁴ HEDPS, Center for Applied Physics and Technology, Peking University, 100871 Beijing, PR China

Received: 28 February 2013
Accepted: 8 May 2013

Abstract

Aims. We present results of the electron-impact broadening parameters (i.e., widths and shifts) of spectral lines in singly ionized Be II, Sr II, and Ba II ions, calculated by using our relativistic quantum mechanical methods.

Methods. In these calculations, Dirac R-matrix methods were used to solve (N + 1)- electron colliding systems to obtain the required scattering matrices. The dimensionless collision strength Ω(ε) is calculated as a function of incident electron energies ε.

Results. The present line-broadening parameters are required for future spectral analysis by means of state-of-the-art nonlocal thermodynamic equilibrium atmospheres, which is now hampered largely by the paucity of reliable atomic and accurate line-broadening data tables. Our results for the spectral line-broadening parameters in the case of three ions obtained for a set of electron temperatures at an electron density 10¹⁷ cm^-3 show very good agreement with other theoretical calculations, and are much closer to the available experimental measurements.