Related Experiment Video
Updated: Oct 9, 2025

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−
Published on: July 27, 2018
Single photon double and triple ionization of allene
Veronica Ideböhn1, Alistair J Sterling2, Måns Wallner1
1Department of Physics, University of Gothenburg, Origovägen 6B, 412 58 Gothenburg, Sweden. raimund.feifel@physics.gu.se.
Abstract:
Double and triple ionization of allene are investigated using electron-electron, ion-ion, electron-electron-ion and electron-electron-ion-ion (ee, ii, eei, eeii) coincidence spectroscopies at selected photon energies. The results provide supporting evidence for a previously proposed roaming mechanism in H3+ formation by double ionization. The lowest vertical double ionization energy is found to be 27.9 eV, while adiabatic double ionization is not accessed by vertical ionization at the neutral geometry. The triple ionization energy is found to be close to 50 eV in agreement with theoretical predictions. The doubly charged parent ion is stable up to about 2 eV above the threshold, after which dissociations by charge separation and by double charge retention occur with comparable intensities. Fragmentation to H+ + C3H3+ starts immediately above the threshold as a slow (metastable) decay with 130.5 ± 9.9 ns mean lifetime.
More Related Videos
Related Concept Videos
Preparation of Alkynes: Dehydrohalogenation
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
Mass Spectrometry: Alkene Fragmentation
Electrophilic Addition to Alkynes: Halogenation
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
π Molecular Orbitals of the Allyl Cation and Anion
Introduction to Electrophilic Addition Reactions of Alkenes
Addition and elimination...
Mass Spectrometry: Alkyne Fragmentation

