Electron impact N-shell excitation of Se-like to Ga-like tungsten ions and polarization of their subsequent emissions

Abstract

Study of electron impact excitation of W40+ (Se-like), W41+ (As-like), W42+ (Ge-like), and W43+ (Ga-like) ions using fully relativistic distorted wave theory has been presented. The excitation cross-sections of E1 and E2 allowed transitions of these ions are reported across the wide range of incident electron energies from excitation threshold to 20 keV. The obtained cross-sections of all the transitions of the four ions are fitted with an analytical expression for the applications in the plasma modelling. Further, using the magnetic sublevel cross-sections, the degree of linear polarization of the photon emissions from the electron impact excited anisotropic states of tungsten ions through the dipole allowed transitions are also calculated.