Ejection of Coulomb Crystals from a Linear Paul Ion Trap for Ion-Molecule Reaction Studies.

摘要: Coulomb crystals are being increasingly employed as a highly localized source of cold ions for the study ion-molecule chemical reactions. To extend scope reactions that can be studied in crystals-from simple involving laser-cooled atomic ions, to more complex systems where molecular reactants give rise multiple product channels-sensitive detection methodologies required. The use digital ion trap (DIT) and new damped cosine (DCT) described, which facilitate ejection Coulomb-crystallized onto an external detector recording time-of-flight (TOF) mass spectra. This enables examination reaction dynamics kinetics between neutral molecules: ionic products typically cotrapped, thus ejecting crystal reveals masses, identities, quantities all species at selected point reaction. Two examined: Ca(+) with deuterated isotopologues water, charge exchange cotrapped Xe(+) ammonia. These examples two distinct types experiment, first direct second sympathetically-cooled heavy form mixture light ions. Extensive simulations conducted interpret experimental results calculate optimal operating parameters, facilitating comparison DIT DCT approaches. also demonstrate correlation shape image on detector, suggesting possible means determining geometry nonfluorescing