Electron impact excitation of Ge-like to Cu-like xenon ions in the extreme ultraviolet

Abstract

Electron impact excitation of Ge-like (Xe22+) to Cu-like (Xe25+) highly charged xenon ions are studied and dipole allowed fine-structure transitions in the wavelength range 9–25 nm are considered. We use relativistic distorted wave method to calculate the electron excitation cross sections for the different transitions of the four ions in the scattered electron energy range from excitation threshold to 1500 eV. The ionic bound state wavefunctions have been obtained using multi-configuration Dirac–Fock method. To ascertain the accuracy of the wavefunctions, the wavelengths and oscillator strengths of the considered transitions in these ions are calculated and compared with the previously reported measurements and other theoretical calculations, where available. For plasma diagnostic applications, the obtained cross sections are further used to calculate the rate coefficients of the transitions as well as fitted with an analytical expression which can be used in plasma model conveniently.