RELATIVISTIC K-SHELL IONIZATION OF HEAVY-ATOMS BY ELECTRON-IMPACT - USE OF A RELATIVISTIC HELIUM-LIKE BOUND-STATE WAVE-FUNCTION

The effect of the correlation between the two K shell electrons on the relativistic triple differential cross section of the simple K shell ionisation of some heavy atoms by very energetic electrons (300, 500 k eV) is studied. A relativistic first Born procedure is developed which permits the use of a variational relativistic helium-like wave functi on for the description of the two K shell electrons, and the introduct ion of the nuclear term in the perturbation potential. The results obt ained by the neglect of the relativistic part of the electron-electron interaction, and thus spin flip, show the effect of the initial state correlation when compared to relativistic plane wave Born calculation s. This work is a first step for future applications of many electrons relativistic models in the heavy atom e, 2e calculations.