THE ROLE OF PROMPT ELECTRONS IN THE POSTCOLLISION EFFECT IN FAST ION-ATOM COLLISIONS

The influence of the post-collision Coulomb effect of direct-electrons on the Auger-line energy shift has been studied in fast proton-atom c ollisions. KLL and LMM Auger spectra of neon and krypton target have b een measured and analysed with high precision. The semiclassical theor y of the post-collision interaction (PCI) has been extended to include the effect of both the receeding projectile ion and the ejected promp t electron. Experimental and theoretical line-energy shifts exhibit a reasonable agreement in the entire angular range of the Auger emission . In a narrow cone around 0 degrees, the line-energy shift is influenc ed mainly by the PCI with the projectile ion, while at backward angles , it is predominantly governed by the ejected electron-Auger-electron interaction.