Xe [ital L] and [ital M] x-ray emission following Xe[sup 44--48+] ion impact on Cu surfaces

The x-ray emission following the impact of highly charged Xe[sup [ital q]+] ([ital q]=44--48) ions of 7-keV/[ital q] energy on a Cu surface has been measured. Theoretically we have derived an analytic formula which allows us to calculate the 2[ital l]-[ital nl][prime], 3[ital l]-[ital nl][prime], and 4[ital l]-[ital nl][prime] ([ital n][le]5), [ital L], [ital M], and [ital N] x-ray transition energies averaged over spin and angular-momentum quantum numbers ([ital L] and [ital S]) as a function of the electron occupation numbers ([ital k][sub [ital i]]) for the states [ital Q]=1[ital s][sub 1][sup [ital k]]2[ital s][sub 2][sup [ital k]]2[ital p][sub 3][sup [ital k]]3[ital s][sub 4][sup [ital k]]3[ital p][sub 5][sup [ital k]]3[ital d][sub 6][sup [ital k]]4[ital s] [sub 7][sup [ital k]]4[ital p][sub 8][sup [ital k]]4[ital d][sub 9][sup [ital k]]4[ital f][sub 10][sup [ital k]]5[ital s][sub 11][sup [ital k]]5[ital p][sub 12][sup [ital k]]. In accordance with our theoretical predictions the observed [ital L] x-ray structures shift toward higher energies and increase in intensity relative to the [ital M] x rays with increasing charge state. We have also observed an increase in high-energy satellite-line intensities with the increasing number of 2[ital p] vacancies. In calculating the radiative-transition probabilities we have found that the dominating electric-dipole transitions for [ital L] and [ital M] x rays are of the kind 2[ital p]-3[ital d] and 3[ital d]-4[ital f], respectively. A comparison between measured peak positions and calculated transition energies reveals that direct feeding by approximately 13 electrons can explain the main features of the observed x-ray emission spectra.