High resolution L Auger electron spectra from fast projectile ions studied by zero-degree electron spectroscopy

In 64-MeV S5+ + He and 90-MeV Sc8+ + He collisions, the light target atom He was used to excite or ionize selectively the L shell of the sulfur and scandium projectiles. The subsequent L-shell Auger emission from Na-like S5+ and Mg-like Sc9+ was measured with high resolution using zero-degree Auger spectroscopy. For 64-MeV S5+ + He collisions, the spectra are dominated by the line groups attributed to the configurations 1s(2)2s(2)2p(5)3snl for n > 3. For 90-MeV Sc8+ + He collisions, the spectra are dominated by the three peak groups that are attributed to the transitions from 1s(2)2s(2)2p(5)3s(2)3p to 1s(2)2s(2)2p(6)3s, 1s(2)2s(2)2p(6)3p, and 1s(2)2s(2)2p(6)3d. It was found that the last Auger transition for Se9+ involves three electrons via electron correlation and this result was compared with the previous results for the isoelectronic ions of Alt and Ar6+. (C) 1998 Elsevier Science B.V.