Autodetachment from Vibrationally Excited Vinylidene Anions

Jessalyn A. DeVine, Marissa L. Weichman, Changjian Xie, Mark C. Babin, Mark A. Johnson, Jianyi Ma, Hua Guo, Daniel M. Neumark

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Slow electron velocity-map imaging of the cryogenically cooled H2CC̄ anion reveals a strong dependence of its high-resolution photoelectron spectrum on detachment photon energy in two specific ranges, from 4000 to 4125 cm-1 and near 5020 cm-1. This effect is attributed to vibrational excitation of the anion followed by autodetachment to H2CC + ē. In the lower energy range, the electron kinetic energy (eKE) distributions are dominated by two features that occur at constant eKEs of 114(3) and 151.9(14) cm-1 rather than constant electron binding energies, as is typically seen for direct photodetachment. These features are attributed to ΔJ = ΔK = 0 autodetachment transitions from two vibrationally excited anion states. The higher energy resonance autodetaches to neutral eigenstates with amplitude in the theoretically predicted shallow well lying along the vinylidene-acetylene isomerization coordinate. Calculations provide assignments of all autodetaching anion states and show that the observed autodetachment is facilitated by an intersection of the anion and neutral surfaces.

Original languageEnglish (US)
Pages (from-to)1058-1063
Number of pages6
JournalJournal of Physical Chemistry Letters
Issue number5
StatePublished - Mar 1 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Physical and Theoretical Chemistry


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