Double Ionization to CO2 Produces Molecular Oxygen: A Roaming Mechanism

Fuente: arXiv
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Main Authors: Ma, Qibo, Hao, Xintai, Zhou, Jiaqi, Xue, Xiaorui, Zeng, Qingrui, Li, Peng, Wang, Lei, Ren, Xueguang
Format: Preprint
Published: 2025
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_version_ 1866912574343217152
author Ma, Qibo
Hao, Xintai
Zhou, Jiaqi
Xue, Xiaorui
Zeng, Qingrui
Li, Peng
Wang, Lei
Ren, Xueguang
author_facet Ma, Qibo
Hao, Xintai
Zhou, Jiaqi
Xue, Xiaorui
Zeng, Qingrui
Li, Peng
Wang, Lei
Ren, Xueguang
contents We report a combined experimental and theoretical study on the formation of O2+ by electronimpact double ionization and fragmentation of carbon dioxide (CO2) molecule. Through fragment ions and electron coincidence momentum imaging, we determine unambiguously the ionization mechanism by measuring the projectile energy loss in association with the C+ + O2+ channel. Further potential energy and trajectory calculations enable us to elucidate the dynamical details of this fragmentation process, in which a bond rearrangement pathway is found to proceed via the structural deformation to a triangular intermediate. Moreover, we demonstrate a new roaming pathway for formation of O2+ from CO22+, in which a frustrated C-O bond cleavage leaves the O atom without sufficient energy to escape. The O atom then wanders around varied configuration spaces of the flat potential energy regions and forms a C-O-O2+ intermediate prior to the final products C+ + O2+. Considering the large quantities of free electrons in interstellar space, the processes revealed here are expected to be significant and should be incorporated into atmospheric evolution models.
format Preprint
id arxiv_https___arxiv_org_abs_2509_05626
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Double Ionization to CO2 Produces Molecular Oxygen: A Roaming Mechanism
Ma, Qibo
Hao, Xintai
Zhou, Jiaqi
Xue, Xiaorui
Zeng, Qingrui
Li, Peng
Wang, Lei
Ren, Xueguang
Atomic and Molecular Clusters
Chemical Physics
We report a combined experimental and theoretical study on the formation of O2+ by electronimpact double ionization and fragmentation of carbon dioxide (CO2) molecule. Through fragment ions and electron coincidence momentum imaging, we determine unambiguously the ionization mechanism by measuring the projectile energy loss in association with the C+ + O2+ channel. Further potential energy and trajectory calculations enable us to elucidate the dynamical details of this fragmentation process, in which a bond rearrangement pathway is found to proceed via the structural deformation to a triangular intermediate. Moreover, we demonstrate a new roaming pathway for formation of O2+ from CO22+, in which a frustrated C-O bond cleavage leaves the O atom without sufficient energy to escape. The O atom then wanders around varied configuration spaces of the flat potential energy regions and forms a C-O-O2+ intermediate prior to the final products C+ + O2+. Considering the large quantities of free electrons in interstellar space, the processes revealed here are expected to be significant and should be incorporated into atmospheric evolution models.
title Double Ionization to CO2 Produces Molecular Oxygen: A Roaming Mechanism
topic Atomic and Molecular Clusters
Chemical Physics
url https://arxiv.org/abs/2509.05626