EXCITATION MECHANISMS OF 2S(1/2)-2P(3/2) AND 2P(1/2)-2P(3/2) TRANSITIONS IN U82+ THROUGH U89+

A model based on detailed calculations of the electron-impact excitation of n = 2 electrons was developed to interpret and explain measurements on EBIT (Electron Beam Ion Trap). While only considering the direct excitation process provided a good model for the electric dipole (El) transitions, it was necessary for the magnetic dipole (Mi) spectrum to include various additional excitation processes in the model. In particular, the model was expanded to include electron-impact excitation of n = 3 levels followed by radiative cascades. Moreover, excitation by the ionization of 2s(1/2), 2p(1/2), and 2p(3/2) electrons and by radiative capture of beam electrons into excited levels was added. The new model demonstrates that the dipole-forbidden lines are almost exclusively produced by indirect excitation processes.