Dominant two-center electron-electron interactions in collisions of 120-mev ne(sup 6+) ions with gas targets

Abstract

The target gases H2, He, CH4, N2, Ne, andAr were bombarded by 120-MeV Ne6+ ions to study the 2s-nl excitation from the metastable state 1s 22s2p 3P0 of the Ne6+ projectile. The Coster-Kronig electrons from the transition 1s 22pnl (n ~ 7)-ls22s +e- were measured using the method of zero-degree electron spectroscopy. It was found that the production cross section for the Coster-Kronig electrons is roughly proportional to the target atomic number. The experimental data are in agreement with impact-parameter calculations, which take in to account the quenching o f the 3 P 0 metastable state o f the projectile, by exciting or ionizing its 2p electron. This agreement supports the conclusion that the dielectronic two-center process is dominant in the production of Coster-Kronig electrons following the 2s-nl excitation of the projectile by H2 and He targets (>56%), and remains significant for the other investigated targets ( > 22%).