Ion-Beam Neutralization-Reionization Spectroscopy of Ion-Pair Formation in Reactions ofHe*(2S3)andHe*(2S1)withO2

Abstract

For ${\mathrm{He}}^{+}$ beams neutralized in alkali vapors and reionized in ${\mathrm{O}}_2$ gas, information on the intermediate neutral states has been used for the first time to isolate the differential cross sections for ion-pair formation in a pair of reactions occurring simultaneously. The reactions of ${\mathrm{He}}^{*}\left(2\mathrm{}{}_{}{}^3{}_{}{}^{}S\right)$ and ${\mathrm{He}}^{*}\left(2\mathrm{}{}_{}{}^1{}_{}{}^{}S\right)$ with ${\mathrm{O}}_2$ are strongly coupled by a shared Coulombic product channel, and evidence exists for unique three-surface trajectories leading to ion-pair products ${\mathrm{He}}^{+}$ + ${\mathrm{O}}_2^{-}$.