Post-collisional Stark mixing in Auger processes

Post-collisional effects on the electronic distribution of autoionization processes are studied. A formulation including both the long range of the projectile Coulomb potential and the polarization potential is presented. The latter potential mixes close lying levels of autoionizing states with equal magnetic quantum number, giving rise to a significant perturbation of the angular and energy distribution of the electron spectra. Particular attention is paid to the mixing of autoionizing levels of helium 2s2p ${}_{}{}^1{}_{}{}^{}$P and 2${\mathit{p}}^2$ ${}_{}{}^1{}_{}{}^{}$D. Deviation from 90° symmetry is studied, and comparison with experiments is presented.