Dynamics and Energy Relaxation of Formic Acid Dimers Following Inner Valence Ionization.
7 affiliations
- 1School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia30332, United States.
- 2Department of Chemistry, Tamkang University, Tamsui, New Taipei City251301, Taiwan.
- 3Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States.
- 4Institut für Kernphysik, Goethe-Universität, 60438Frankfurt am Main, Germany.
- 5J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas66506, United States.
- 6Department of Physics, University of Nevada, Reno, Nevada89557, United States.
- 7School of Physics, Georgia Institute of Technology, Atlanta, Georgia30332, United States.
Abstract
We study gas-phase dissociation of the formic acid dimer dication as a model for DNA base-pair interactions after inner-valence 56 eV extreme ultraviolet (EUV) ionization. Employing reaction microscopy, we measure the 3D momenta of electrons and fragment-ions in coincidence to reconstruct channel-resolved electron kinetic energies, fragment kinetic energy release, and angular distributions. This work focuses on the symmetric 2-body (HCOOH+ + HCOOH+) and asymmetric 3-body (HCOOH+ + HCOO+ + H) breakup channels, reporting their relative yields and dynamics. Electron-energy signatures and angular correlations distinguish direct double ionization (DDI) from sequential ionization (SI) with a ratio of ∼9:5. In SI, low-energy electrons and their near-isotropic angular distributions indicate a competition between local intramolecular autoionization (AI) and nonlocal intermolecular Coulombic decay (ICD). Real-time simulations of the electron dynamics support AI/ICD-driven secondary ionization on sub-20 fs time scales. The SI process depends on whether the initially ionized orbital has carbonyl- or hydroxyl-oxygen character, with charge and energy transfer occurring between diagonally adjacent oxygen atoms rather than along hydrogen bonds.
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BibTeX
@article{manis2026dynamics,
title = {{Dynamics and Energy Relaxation of Formic Acid Dimers Following Inner Valence Ionization.}},
author = {J X Zhong Manis and Y S Wang and M C Rohan and S Kumar and M Shaikh and J Stindl and G Kastirke and O D McGinnis and M Kircher and C Bagdia and N Iwamoto and R Enoki and V Davis and J B Williams and R Dörner and I Ben-Itzhak and D S Slaughter and T Weber and J S Kretchmer and T M Orlando},
journal = {The journal of physical chemistry letters},
year = {2026},
month = oct,
doi = {10.1021/acs.jpclett.6c03064},
url = {https://europepmc.org/article/MED/42918232},
note = {CC BY},
}
RIS
TY - JOUR
TI - Dynamics and Energy Relaxation of Formic Acid Dimers Following Inner Valence Ionization.
AU - J X Zhong Manis
AU - Y S Wang
AU - M C Rohan
AU - S Kumar
AU - M Shaikh
AU - J Stindl
AU - G Kastirke
AU - O D McGinnis
AU - M Kircher
AU - C Bagdia
AU - N Iwamoto
AU - R Enoki
AU - V Davis
AU - J B Williams
AU - R Dörner
AU - I Ben-Itzhak
AU - D S Slaughter
AU - T Weber
AU - J S Kretchmer
AU - T M Orlando
PY - 2026
DA - 2026/10/01
JO - The journal of physical chemistry letters
DO - 10.1021/acs.jpclett.6c03064
UR - https://europepmc.org/article/MED/42918232
AB - We study gas-phase dissociation of the formic acid dimer dication as a model for DNA base-pair interactions after inner-valence 56 eV extreme ultraviolet (EUV) ionization. Employing reaction microscopy, we measure the 3D momenta of electrons and fragment-ions in coincidence to reconstruct channel-resolved electron kinetic energies, fragment kinetic energy release, and angular distributions. This work focuses on the symmetric 2-body (HCOOH+ + HCOOH+) and asymmetric 3-body (HCOOH+ + HCOO+ + H) breakup channels, reporting their relative yields and dynamics. Electron-energy signatures and angular correlations distinguish direct double ionization (DDI) from sequential ionization (SI) with a ratio of ∼9:5. In SI, low-energy electrons and their near-isotropic angular distributions indicate a competition between local intramolecular autoionization (AI) and nonlocal intermolecular Coulombic decay (ICD). Real-time simulations of the electron dynamics support AI/ICD-driven secondary ionization on sub-20 fs time scales. The SI process depends on whether the initially ionized orbital has carbonyl- or hydroxyl-oxygen character, with charge and energy transfer occurring between diagonally adjacent oxygen atoms rather than along hydrogen bonds.
SN - 1948-7185
ER -