Relativistic distorted-wave procedures with pseudostates

Abstract

The relativistic distorted-wave (RDW) procedures developed by Chen [Phys. Rev. A 53, 3227 (1996)] have been extended to include pseudostates. The RDW procedures with pseudostates are applied to the calculation of electron impact excitation (EIE) of Fe XVII. Pseudostates are shown to have a significant effect on the cross sections for important transitions such as 3C ({lambda}=15.015 A) and 3D ({lambda}=15.262 A) of Fe XVII. The convergence of the RDW calculations has been carefully investigated. The present RDW calculations of Fe XVII are further compared with our previous close coupling results using the fully relativistic Dirac R-matrix (DRM) method, where resonance and more complete channel coupling effects were included in addition to the background direct excitations. The present RDW calculations are in good agreement to the background cross sections from the DRM calculations. This agreement indicates the mutual confirmation of the validity of both the RDW and the DRM calculations of the direct or background EIE cross sections.