title: Double ionization of cycloheptatriene and the reactions of the resulting C7H(n)2+ dications (n = 6, 8) with xenon.
abstract: The formation and fragmentation of the molecular dication C(7)H(8)(2+) from cycloheptatriene (CHT) and the bimolecular reactivities of C(7)H(8)(2+) and C(7)H(6)(2+) are studied using multipole-based tandem mass spectrometers with either electron ionization or photoionization using synchrotron radiation. From the photoionization studies, an apparent double-ionization energy of CHT of (22.67 ± 0.05) eV is derived, and the appearance energy of the most abundant fragment ion C(7)H(6)(2+), formed via H(2) elimination, is determined as (23.62 ± 0.07) eV. Analysis of both the experimental data as well as results of theoretical calculations strongly indicate, however, that an adiabatic transition to the dication state is not possible upon photoionization of neutral CHT and the experimental value is just considered as an upper bound. Instead, an analysis via two different Born-Haber cycles suggests (2)IE(CHT) = (21.6 ± 0.2) eV. Further, the bimolecular reactivities of the C(7)H(n)(2+) dications (n = 6, 8), generated via double ionization of CHT as a precursor, with xenon as well as nitrogen lead, inter alia, to the formation of the organo-xenon dication C(7)H(6)Xe(2+) and the corresponding nitrogen adduct C(7)H(6)N(2)(2+).
authors.affiliation: Department of Physics, University of Trento, Via Sommarive 14, 38123 Povo, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Ascenzi
authors.forename: Julia
authors.initials: J
authors.lastname: Aysina
authors.forename: Emilie-Laure
authors.initials: EL
authors.lastname: Zins
authors.forename: Detlef
authors.initials: D
authors.lastname: Schröder
authors.forename: Jan
authors.initials: J
authors.lastname: Žabka
authors.forename: Christian
authors.initials: C
authors.lastname: Alcaraz
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Price
authors.forename: Jana
authors.initials: J
authors.lastname: Roithová