Experimental and theoretical results on electron emission in collisions between partially-dressed ions with He targets

J.M. MONTI; D. FREGENAL; S. SUÁREZ; E. HORSDAL; W. WOLFF; P. D. FAINSTEIN; R. D. RIVAROLA; G. BERNARDI; J. FIOL

Heidelberg

Conferencia; Physics of Highly Charged Ions; 2012

The study of electronic reactions in collisions between partially-dressed projectiles with atomictargets has received increasing interest over the last two decades. These systems have providedsuitable framework to investigate the relative importance of the electron-electron interaction incomparison to the interaction of the emitted electron with the screened nucleus.In this work we present experimental and theoretical results on the electron emission betweenswift partially-dressed Liq+ and Alq+ ions (q = 1, 2, 3) impinging on He atoms. The interestingfeature of these systems relies on the fact that in both cases the projectile electrons are notbound enough to be considered passive electrons (frozen in their orbitals during all the reaction)and thus target, projectile and even simultaneous ionization can occur.Experimental doubly differential cross sections for electron emision induced by intermediateenergy projectiles are compared with classical CTMC and quantum CDW and CDW-EIStheoretical models. In the case of CTMC, electrons from both centers are considered. Theinteractions of the electrons with both nuclei as well as the interaction between electrons fromdifferent centers are shown to produce ionization. The quantum CDW and CDW-EIS models,originally developed to the case of bare projectiles, where recently extended to the case of partially-dressed ones. In this extension the target active electron-projectile interaction is approximated in terms of a GSZ two-parameter potential.Results of doubly differential cross sections as a function of electron energy for a wide varietyof angles and several impact energies will be presented at the conference along with theoreticaldetails. The comparison between the three theories, and with the experimental data, allow us todiscuss the role played by short- and long-range interactions, as well as the relative importanceof target, projectile and simultaneous ionization in the observed spectra.