RECOMBINATION IN KR34++H-2 COLLISIONS

Recombination of Kr34+ ions in collisions with H-2 has been investigat ed. The principal motivation for this work was to search for resonant electron-transfer double excitation (RT2E), a three-electron correlati on mechanism that is expected to occur in an ion-atom collision when e lectron transfer is accompanied by the simultaneous (resonant) excitat ion of two electrons to form an intermediate excited state. As a bench mark for RT2E, measurements of resonant transfer excitation (RTE) were made first. In this work, Kr (mostly K-shell) x-ray emission associat ed with single-electron-capture events was detected. Events associated with RTE were readily observed, but no events associated with RT2E we re observed to a sensitivity of about 10(-25) cm(2). However, x rays a ssociated with capture did occur at about twice the Kr K x-ray energy The change in the x-ray energy of these latter events with beam energy indicates that radiative electron capture (REC) (inverse photoelectri c effect) is the mechanism responsible. The observed cross sections fo r both the RTE and REC mechanisms are in reasonable agreement with the oretical calculations.