Study of electron impact fine-structure excitation and polarization of highly charged tungsten ions

Study of electron-impact excitation of few highly charged tungsten ions viz. Tm-, Er- and Ho-like has been done using relativistic distorted wave theory (RDW). The dipole allowed transitions of these ions are considered and electron-impact excitation cross section are reported in the wide range of energy. These calculated cross section are also fitted with suitable analytical expressions for the direct use in plasma modelling. Further-more, the polarization of the emitted photons on consequent decay of the excited tungsten ions are calculated by utilizing density matrix theory.