XE-L AND M X-RAY-EMISSION FOLLOWING XE-44-48+ ION IMPACT ON CU SURFACES

The x-ray emission following the impact of highly charged Xe(q+) (q = 44-48) ions of 7-keV/q energy on a Cu surface has been measured. Theor etically we have derived an analytic formula which allows us to calcul ate the 21 -nl', 31 -nl', and 41 -nl' (n less-than-or-equal-to 5), L, M, and N x-ray transition energies averaged over spin and angular-mome ntum quantum numbers (L and S) as a function of the electron occupatio n numbers (k(i)) for the states Q = 1k2s2k2p3k3s4k3p5k3d6k4s7k4p8k4d9k 4f10k5s11k5p12k. In accordance with our theoretical predictions the ob served L x-ray structures shift toward higher energies and increase in intensity relative to the M x rays with increasing charge state. We h ave also observed an increase in high-energy satellite-line intensitie s with the increasing number of 2p vacancies. In calculating the radia tive-transition probabilities we have found that the dominating electr ic-dipole transitions for L and M x rays are of the kind 2p - 3d and 3 d - 4f, respectively. A comparison between measured peak positions and calculated transition energies reveals that direct feeding by approxi mately 13 electrons can explain the main features of the observed x-ra y emission spectra.