Electron impact excitation cross section measurements of highly charged heliumlike and lithiumlike ions

摘要

The cross sections for electron impact excitation of the heliumlike forbidden line z, intercombination lines y and x, and the resonance line w, together with the associated lithiumlike satellites lines q, r, t, u, and v have been measured for Ti, V, Cr, Mn, and Fe on the Livermore electron beam ion trap. The measurements were made near the threshold for excitation of the heliumlike transitions where no other processes can contribute to the excitation of the lines. The uncertainties in the measurements are up to 15% for the heliumlike transitions and between 14 and 27% for the lithiumlike transitions. We find good agreement with results from a distorted-wave calculation.