University of Illinois Urbana-Champaign

SPECTROSCOPIC PROBING OF LOW-TEMPERATURE ION-MOLECULE REACTIONS

Brünken, Sandra

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6700.pdf
RG01_1.pptx

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https://hdl.handle.net/2142/122385

Description

Title
SPECTROSCOPIC PROBING OF LOW-TEMPERATURE ION-MOLECULE REACTIONS
Author(s)
Brünken, Sandra
Contributor(s)
  • Redlich, Britta
  • Marimuthu, Aravindh Nivas
  • Schrauwen, Johanna G.M.
  • Rap, Daniel
Issue Date
2023-06-22
Keyword(s)
Mini-symposium: Spectroscopy with Cryogenic Ion Traps
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are abundant in many regions of the Universe, representing a major reservoir for cosmic carbon. However, their formation pathways in cold regions of space, such as dense molecular clouds and Titan's atmosphere, remain elusive despite the recent advances in the detection of aromatic molecules there. Astronomical observations show that astrochemical models significantly underestimate the abundance of these aromatic molecules, indicating that efficient formation pathways, such as ion-molecule reactions involving aromatic ions and hydrocarbon neutrals, are likely missing in the existing models. In our work, we use a cryogenic 22-pole ion trap apparatus to study ion-molecule reactions at low temperature, and to structurally identify ionic reactants, reaction intermediates and products in-situ employing infrared-predissociation (IRPD) and infrared multiple-photon dissociation (IRMPD) spectroscopy using the infrared free-electron lasers at the FELIX Laboratory. We reveal efficient low-temperature formation pathways towards PAHs and related species via exothermic ion-molecule reactions. The experimental approach combines kinetic and spectroscopic studies, and unambiguously identifies key reaction intermediates, and, in the case of the reaction of pyridine⁺ with acetylene, the final nitrogen-containing PAH product ion quinolizinium⁺. These studies not only reveal competing formation pathways relevant in cold astronomical environments, but also deliver a variety of information to verify in-silico potential energy surfaces, astronomical models, and to guide infrared observations.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
Text
Genre of Resource
Conference Paper / Presentation
Language
eng
Handle URL
https://hdl.handle.net/2142/122385
DOI
https://doi.org/10.15278/isms.2023.6700

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Abstracts & Presentations - 2023 International Symposium on Molecular Spectroscopy PRIMARY