Relativistic B-Spline R-Matrix Calculations for Electron Collisions with Tantalum

Abstract To fulfill the requirements of spectral analysis and plasma modeling, we carried out an extensive theoretical investigation of the electron-impact excitation of atomic Ta. The fully relativistic Dirac B -spline R -matrix (DBSR) method was employed to deal with the complicated open d -shell structure of Ta and subsequent problem of e -Ta collision. We calculated 63 low-lying fine-structure levels of 5 d 3 6 s 2 , 5 d 4 6 s , 5 d 2 6 s 2 6 p and 5 d 3 6 s 6 p configurations with consideration of their strong term dependence of the orbitals and configuration mixing. Comprehensive sets of radiative parameters are reported for all of the possible dipole-allowed transitions between those levels. Comparison was made with available values from the NIST database, and overall agreement can be found. Predictions for electron-impact excitation cross sections are presented for incident energies from threshold to 100 eV. The present DBSR calculations addressed the scarcity of radiative and electron collisional data for atomic Ta and expanded its available database.