Electron capture induced fragmentation of CO$_2^{3+}$: Influence of projectile charge on sequential and concerted break-up pathways

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Hauptverfasser: Srivastav, Akash, Srivastav, Sumit, Bapat, Bhas
Format: Preprint
Veröffentlicht: 2026
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author Srivastav, Akash
Srivastav, Sumit
Bapat, Bhas
author_facet Srivastav, Akash
Srivastav, Sumit
Bapat, Bhas
contents We investigate the $\text{O}^+:\text{C}^+:\text{O}^+$ fragmentation channel of CO$_2^{3+}$ produced in slow collisions with Ar$^{q+}$ projectiles ($4 \le q \le 16$, velocities $\approx 0.3$ a.u). Using the native-frames method, we disentangle the sequential and concerted break-up processes and their corresponding kinetic energy release (KER) distributions. \emph{Ab initio} potential energy curves of CO$_2^{3+}$ are calculated and mapped to the KER spectra to identify the underlying electronic states involved in the fragmentation. While the sequential KER distributions remain nearly unchanged for across the projectile charge range, the concerted KER distributions exhibit pronounced but non-systematic variations with projectile charge. In addition, a low KER feature around 15.5 eV -- previously associated with sequential break-up in electron and proton impact -- is observed for Ar$^{4+}$ impact and, to a lesser extent, for Ar$^{6+}$ impact. It originates predominantly from concerted break-up of the low-lying $^2Π_\text{g}$ and $^{2,4}Π_\text{u}$ states. Branching ratios of the two break-up pathways deviate from simple monotonic trends for certain projectiles, but barring these exceptions, the fraction of concerted break-up decreases with increasing $q$, while that for sequential break-up increases. These findings underscore the necessity of accounting for the detailed electronic structure of the projectile, rather than its charge alone, to achieve a comprehensive understanding of collisional dynamics in slow, highly charged ion collisions.
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id arxiv_https___arxiv_org_abs_2601_03711
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Electron capture induced fragmentation of CO$_2^{3+}$: Influence of projectile charge on sequential and concerted break-up pathways
Srivastav, Akash
Srivastav, Sumit
Bapat, Bhas
Atomic Physics
Chemical Physics
We investigate the $\text{O}^+:\text{C}^+:\text{O}^+$ fragmentation channel of CO$_2^{3+}$ produced in slow collisions with Ar$^{q+}$ projectiles ($4 \le q \le 16$, velocities $\approx 0.3$ a.u). Using the native-frames method, we disentangle the sequential and concerted break-up processes and their corresponding kinetic energy release (KER) distributions. \emph{Ab initio} potential energy curves of CO$_2^{3+}$ are calculated and mapped to the KER spectra to identify the underlying electronic states involved in the fragmentation. While the sequential KER distributions remain nearly unchanged for across the projectile charge range, the concerted KER distributions exhibit pronounced but non-systematic variations with projectile charge. In addition, a low KER feature around 15.5 eV -- previously associated with sequential break-up in electron and proton impact -- is observed for Ar$^{4+}$ impact and, to a lesser extent, for Ar$^{6+}$ impact. It originates predominantly from concerted break-up of the low-lying $^2Π_\text{g}$ and $^{2,4}Π_\text{u}$ states. Branching ratios of the two break-up pathways deviate from simple monotonic trends for certain projectiles, but barring these exceptions, the fraction of concerted break-up decreases with increasing $q$, while that for sequential break-up increases. These findings underscore the necessity of accounting for the detailed electronic structure of the projectile, rather than its charge alone, to achieve a comprehensive understanding of collisional dynamics in slow, highly charged ion collisions.
title Electron capture induced fragmentation of CO$_2^{3+}$: Influence of projectile charge on sequential and concerted break-up pathways
topic Atomic Physics
Chemical Physics
url https://arxiv.org/abs/2601.03711