Ionization of neutral W and W$^+$ ion by electron impact

Ionization cross sections for the neutral W and W$^+$ ion by electron impact are being calculated using binary-encounter- Bethe (BEB) model for the direct ionization and scaled Born cross sections for excitation-autoionization as was done successfully for the ionization of C, N, and O.\footnote{Y.-K. Kim and J. P. Desclaux, Phys. Rev. A {\bf 66}, 012708 (2002).} Two sets of experimental data for W$^+$ are available in the literature, while there are no experimental data for the neutral W. Both sets of the experimental data indicate the presence of metastable W$^+$ ions in their target beams, but the magnitude and shape are comparable to our preliminary results for W$^+$ ion in the ground level. Theoretical results that include cross sections for both direct ionization and excitation-autoionization of W and W$^+$ will be reported at the conference.