Double electron transfer reactions of CO22+ ions

Time-of-flight techniques have been used to measure fast neutral CO2 products from double electron transfer reactions of CO22+ ions with 4.0–7.0 keV impact energies. Double electron transfer cross sections have been determined to be in the range of (1.1–12.5) × 10−16 cm2 for reactions of CO22+ ions with CO2, CO, N2, Ar and O2.

Single- and double-electron transfer reactions of ground and metastable state Ar2+ ions

Electron transfer cross sections have been measured for reactions of Ar2+ ions with Ar, N2, O2, CO2, CH4 and C2H6. Time-of-flight techniques have been used to measure both fast neutral Ar0 and fast Ar+ products from single- and double-electron transfer processes involving Ar2+ ions with 4.0 to 7.0 keV impact energies. Incident Ar2+ ions have produced by controlled electron impact ionisation of argon atoms. Reactions have been examined as a function of ionising electron energy and cross sections determined for ground state Ar2+(3P) ions. Charge transfer cross sections have been determined to be in the range of 3*10-16 cm2 for the systems examined. Double-electron transfer cross sections are the same order of magnitude as those measured for the corresponding single-electron transfer reactions. The state distribution of the reactant ion beam has been estimated and electron transfer cross sections obtained for single- and double-electron transfer reactions of metastable Ar2+ions. The magnitudes of electron transfer cross sections in individual systems are similar for both ground and metastable state Ar2+ reactions.

Competition between single and double electron transfer in collisions of doubly charged molecular pyrrole ions with neutral pyrrole molecules

Cross-sections have been determined for one- and two-electron transfer channels in the collisions of keV gas-phase doubly charged pyrrole ions with pyrrole molecules. Measured single and double electron transfer total cross-sections approximate 45 Å2 and 15 Å2, respectively. A combination of symmetric resonance charge exchange and multistate curve-crossing models has been invoked to describe these reactions.

Evidence for Long-lived Excited States of CnH22+ Carbodications

The energetics, structures, stabilities and reactivities of[CnH2]2+ ions have been investigated using computational methods and experimental mass spectrometric techniques. Spontaneous decompositions of [CnH2]2+ into [CnH]+ + H+ products, observed for ions with odd-n values, have been explained by invoking the formation of excited triplet states. Even-n [CnH]+ ions possess triplet ground states with low-lying excited states, whereas odd-n ions have triplet states with energies several eV above ground singlet states. Radiationless transitions of vibrationally excited long-lived triplet state ions into singlet state continua are suggested as possible mechanisms for spontaneous deprotonation processes of odd-n [CnH2]2+ ions. Evidence for these long-lived excited states has been obtained in bimolecular single electron transfer reactions.