Preprint

PUBDB-2024-01157

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Conformational and state-specific effects in reactions of 2,3-dibromobutadiene with Coulomb-crystallized calcium ions

Kilaj, A. ; Käser, S. ; Wang, J.CFEL*Extern*DESY* ; Straňák, P. ; Schwilk, M. ; Xu, L. ; von Lilienfeld, O. A. ; Küpper, J. (Corresponding author)CFEL*XFEL.EU*DESY* ; Meuwly, M. (Corresponding author) ; Willitsch, S. (Corresponding author)

2023

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Please use a persistent id in citations: doi:10.3204/PUBDB-2024-01157

Report No.: arXiv:2303.11813

Abstract: Recent advances in experimental methodology enabled studies of the quantum-state and conformational dependence of chemical reactions under precisely controlled conditions in the gas phase. Here, we generated samples of selected gauche and s-trans 2,3-dibromobutadiene (DBB) by electrostatic deflection in a molecular beam and studied their reaction with Coulomb crystals of laser-cooled $\mathrm{Ca^{+}}$ ions in an ion trap. The rate coefficients for the total reaction were found to strongly depend on both the conformation of DBB and the electronic state of $\mathrm{Ca^{+}}$. In the $\mathrm{(4p)~^{2}P_{1/2}}$ and $\mathrm{(3d)~^{2}D_{3/2}}$ excited states of $\mathrm{Ca^{+}}$, the reaction is capture-limited and faster for the gauche conformer due to long-range ion-dipole interactions. In the $\mathrm{(4s)~^{2}S_{1/2}}$ ground state of $\mathrm{Ca^{+}}$, the reaction rate for s-trans DBB still conforms with the capture limit, while that for gauche DBB is strongly suppressed. The experimental observations were analysed with the help of adiabatic capture theory, ab-initio calculations and reactive molecular dynamics simulations on a machine-learned full-dimensional potential energy surface of the system. The theory yields near-quantitative agreement for s-trans-DBB, but overestimates the reactivity of the gauche-conformer compared to the experiment. The present study points to the important role of molecular geometry even in strongly reactive exothermic systems and illustrates striking differences in the reactivity of individual conformers in gas-phase ion-molecule reactions.

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Contributing Institute(s):

1. CFEL-CMI (FS-CFEL-CMI)
2. Uni Hamburg / Experimentalphysik (UNI/EXP)
3. beauftragt von UNI (UNI/CUI)

Research Program(s):

1. 631 - Matter – Dynamics, Mechanisms and Control (POF4-631) (POF4-631)
2. DFG project 390715994 - EXC 2056: CUI: Advanced Imaging of Matter (390715994) (390715994)
3. QML - Quantum Machine Learning: Chemical Reactions with Unprecedented Speed and Accuracy (772834) (772834)

Experiment(s):

1. Experiments at CFEL

Appears in the scientific report 2023

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Database coverage:
; ; Published

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Linked articles:

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Journal Article Kilaj, A. (First author) ; Käser, S. ; Wang, J.CFEL*Extern*DESY* ; Stranak, P. ; Schwilk, M. ; Xu, L. ; von Lilienfeld, O. A. ; Küpper, J. (Corresponding author)CFEL*XFEL.EU*DESY* ; Meuwly, M. (Corresponding author) ; Willitsch, S. (Corresponding author)
Conformational and state-specific effects in reactions of 2,3-dibromobutadiene with Coulomb-crystallized calcium ions
Physical chemistry, chemical physics 25(20), 13933 - 13945 (2023) [10.1039/D3CP01416A]2023     Files  Fulltext by arXiv.org BibTeX | EndNote: XML, Text | RIS

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