Electron impact excitation collision strengths and radiative parameters for Sc II spectral lines *

New large-scale calculations for electron impact excitation collision strengths and radiative parameters for Sc II spectral lines between the 145 fine-structure levels belonging to the 3p⁶3d², 3p⁶3d4l (l=0-3), 3p⁶3d5l (l=0-3), 3p⁶3d6s, 3p⁶4s², 3p⁶4s4l (l=0-3), 3p⁶4s5l (l=0-1), and 3p⁶4p² configurations have been performed. Accurate description of the Sc II wave functions and adequate account of the various interactions between target levels are of crucial importance for the calculations of collision and radiative parameters and have been determined by a combination of the multiconfiguration Hartree-Fock and the B-spline box-based close-coupling methods together with the nonorthogonal orbitals technique [1]. The valence electron wave functions are described by multichannel expansions in a B-spline basis and are subjected to a boundary condition to become negligible at the boundary.  This approach generates whole Rydberg series as well as considers the interaction between different series. The calculations of collision strengths have been performed using the close-coupling approximation based on the B-spline Breit-Pauli R-matrix method [2]. The relativistic effects in the scattering calculations have been incorporated in the Breit-Pauli Hamiltonian using the one-body Darwin, mass correction, and spin-orbit operators. The likely uncertainties in our results have been estimated by means of comparison with other calculations and experimental radiative parameters.

 

¹ E-mail: stayal@cau.edu

² E-mail: oleg.zatsarinny@drake.edu

 

[1] Zatsarinny, O. and Froese Fisher, C. 2009 Comp. Phys. Comm. 180, 2041

[2] O. Zatsarinny 2006 Comp. Phys. Commun. 174 273