title: High-resolution (e, 2e + ion) study of electron-impact ionization and fragmentation of methane.
abstract: The ionization and fragmentation of methane induced by low-energy (E0 = 66 eV) electron-impact is investigated using a reaction microscope. The momentum vectors of all three charged final state particles, two outgoing electrons, and one fragment ion, are detected in coincidence. Compared to the earlier study [Xu et al., J. Chem. Phys. 138, 134307 (2013)], considerable improvements to the instrumental mass and energy resolutions have been achieved. The fragment products CH4 (+), CH3 (+), CH2 (+), CH(+), and C(+) are clearly resolved. The binding energy resolution of ΔE = 2.0 eV is a factor of three better than in the earlier measurements. The fragmentation channels are investigated by measuring the ion kinetic energy distributions and the binding energy spectra. While being mostly in consistence with existing photoionization studies the results show differences including missing fragmentation channels and previously unseen channels.
authors.affiliation: Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany.
authors.forename: Xueguang
authors.initials: X
authors.lastname: Ren
authors.affiliation: Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pflüger
authors.affiliation: Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany.
authors.forename: Marvin
authors.initials: M
authors.lastname: Weyland
authors.affiliation: Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany.
authors.forename: Woon Yong
authors.initials: WY
authors.lastname: Baek
authors.affiliation: Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany.
authors.forename: Hans
authors.initials: H
authors.lastname: Rabus
authors.affiliation: Physikalisch-Technische Bundesanstalt, 38116 Braunschweig, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Ullrich
authors.affiliation: Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Dorn