Electron capture by a metastable ion in the collision Ar8+(2p(5)3s)P-3(0,2)+H-2 at low velocity - art. no. 032710

Single-electron (SC) and double-electron capture (DC) in collisions of meta stable Ar8+ ions with H-2 have been studied by using X-VUV and Auger spectr oscopy at 10 keV per charge. SC by the long-lived metastable ion Ar8+(2p(5) 3s)P-3(0.2) mostly populates inner-shell excited Na-like Ar7+**[(2p(5)3s)P- 3,nl]L-2.4(j) levels with n = 5, a small fraction going to n = 4. With the use of radiative and Auger decay rates, the observed X-VUV and Auger spectr a are analyzed and compared with the spectra obtained by other authors. It is shown that the stabilization of these core-excited states is both radiat ive and autoionizing. DC by the metastable projectile reveals the formation of triply excited Ar6+*** ions. They stabilize along two Auger decay steps : the first one gives a low-energy electron, associated with the decay to t he intermediate continua Ar7+(2p(5)3l3l'), while the second step-originatin g from these Ar7+(2p(5)3l3l') levels-gives a higher-energy electron, charac teristic of the decay to the only available continuum Ar8+(2p(6))S-1(0).