ELECTRONIC SPECTROSCOPY OF HYDROGENATED CARBON CLUSTER ISOMERS

Marlton, Samuel Jack Palmer

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https://hdl.handle.net/2142/122529 Copy

Description

Title

ELECTRONIC SPECTROSCOPY OF HYDROGENATED CARBON CLUSTER ISOMERS

Author(s)

Marlton, Samuel Jack Palmer

Contributor(s)

• Watkins, Patrick
• Liu, Chang
• Bieske, Evan

Issue Date

2023-06-19

Keyword(s)

Mini-symposium: Spectroscopy with Cryogenic Ion Traps

Abstract

Highly unsaturated CₓHy⁺ clusters are important in combustion and the chemistry of interstellar space. However, interrogating carbonaceous molecules containing more than 10 carbon atoms is complicated by the coexistence of different isomers possessing unique spectroscopic properties. To disentangle this complexity, we have developed an apparatus that allows formation and selection of a particular CₓHy⁺ isomer population by ion mobility and mass to charge ratio. The selected ions are then incarcerated in a cryogenically cooled ion trap and subjected to tunable radiation. Resonant excitation of an electronic transition leads to cluster fragmentation, which when monitored as a function of wavelength yields an action spectrum. We have also measured electronic spectra for a variety of CₓHy⁺ ions, which are formed by photoionizing and photodissociating PAHs in the ion source. The CₓHy⁺ clusters can be linear or cyclic, but can be selected by their ion mobility arrival time and mass to charge ratio. Pyrene photoproducts include C₂n₊₁H₃⁺ and C₂n₊₁H⁺ clusters. The C₂n₊₁H₃⁺ clusters are mostly linear isomers with characteristic vibronic progressions of low frequency modes (see Figure). C₂n₊₁H⁺ clusters are shown to exist as linear and cyclic isomers that have distinct electronic spectra. These results provide clues on how different CₓHy⁺ cluster isomers form, dissociate, and isomerise in interstellar space, and provide spectroscopic fingerprints to aid their astronomical detection.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Handle URL

https://hdl.handle.net/2142/122529

DOI

https://doi.org/10.15278/isms.2023.7004

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