Electron-Impact Ionization of Atomic Ions in the W Isonuclear Sequence

A configuration-average distorted-wave method is used to calculate electron-impact ionization cross sections and rate coefficients for atomic ions in the W isonuclear sequence. Besides direct ionization, the indirect process of excitation-autoionization is also included. Checks on the validity of the configuration-average approximation are made by comparison with detailed calculations using the level to level multi-configuration distorted-wave method for selected ionization stages. Indirect ionization is found to be greatly reduced due to radiation damping for the higher ionization stages.