title: Probing isotope effects in chemical reactions using single ions.
abstract: Isotope effects in reactions between Mg+ in the 3p{2}P{3/2} excited state and molecular hydrogen at thermal energies are studied through single reaction events. From only approximately 250 reactions with HD, the branching ratio between formation of MgD+ and MgH+ is found to be larger than 5. From an additional 65 reactions with H2 and D2 we find that the overall fragmentation probability of the intermediate MgH2+, MgHD+, or MgD2+ complexes is the same. Our study shows that few single ion reactions can provide quantitative information on ion-neutral reactions. Hence, the method is well suited for reaction studies involving rare species, e.g., rare isotopes or short-lived unstable elements.
authors.affiliation: QUANTOP - Danish National Research Foundation Centre for Quantum Optics, University of Aarhus, 8000 Aarhus, Denmark.
authors.forename: Peter F
authors.initials: PF
authors.lastname: Staanum
authors.forename: Klaus
authors.initials: K
authors.lastname: Højbjerre
authors.forename: Roland
authors.initials: R
authors.lastname: Wester
authors.forename: Michael
authors.initials: M
authors.lastname: Drewsen