<div class="csl-bib-body">
<div class="csl-entry">Enders, V., Nørskov Pedersen, A., Stolze, J., Dinu, D. F., Elm, J., Grothe, H., Podewitz, M., Shabbir, U., & Stolzenburg, D. (2026). <i>Nucleation of α-pinene oxidation products: Molecular level insights from matrix isolation Fourier transform infrared spectroscopy</i> [Conference Presentation]. 12th International Aerosol Conference (IAC 2026), Xi’an, China. http://hdl.handle.net/20.500.12708/231389</div>
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dc.identifier.uri
http://hdl.handle.net/20.500.12708/231389
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dc.description.abstract
New particle formation (NPF) consists of two main steps: nucleation of gas- phase vapors and subsequent growth of the initial molecular clusters. While nucleation is mostly driven by inorganic acids, organic acids, such as oxidation products of α- pinene, are also known to contribute to the mass of fully grown particles. It is, however, not clear which organic molecules can nucleate in the absence of inorganic substances, or at what stage in NPF organic compounds become important. The reason is that current mass spectrometry techniques provide only compositional information and lack structural insights into the configurations of the initial-stage clusters. Here, we show that matrix-isolation Fourier transform infrared spectroscopy (MI-FTIR) can be used to study the initial steps of nucleation on a molecular level. Monomers and dimers of α-pinene oxidation products, such as pinic acid, are isolated in cryogenic argon matrices. By that, spectra are greatly simplified by the suppression of rotational sidebands. Our experiments are complemented by quantum chemical calculations, in which we calculate free energies and harmonic vibrational frequencies. By comparing their results to the experimental data, it is shown that, e.g., the measured dimer spectra of pinic acid fit best to those calculated for a dimer with a single OH-bridge. The existence of these dimer structures, which are not predicted to be the lowest free-energy conformer, could be ideal for subsequent growth. Up to three unbound OH groups are available for further oligomerization in singly-bridged dimers. In addition, our experiment shows that pinic acid forms dimers much more easily than, e.g., pinonic acid. By studying α-pinene oxidation products, we show that MI-FTIR is a versatile tool to investigate the structure of NPF precursor molecules and the very first steps of nucleation. The toolbox of MI-FTIR, in conjunction with theoretical calculations, can readily be applied to other organic NPF precursors.
en
dc.description.sponsorship
FWF - Österr. Wissenschaftsfonds
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dc.language.iso
en
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dc.subject
New particle formation
en
dc.subject
Aerosol nucleation
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dc.subject
Matrix isolation FTIR
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dc.subject
α-pinene
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dc.subject
FTIR
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dc.subject
quantum chemical calculations
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dc.title
Nucleation of α-pinene oxidation products: Molecular level insights from matrix isolation Fourier transform infrared spectroscopy
en
dc.type
Presentation
en
dc.type
Vortrag
de
dc.contributor.affiliation
Aarhus University, Denmark
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dc.contributor.affiliation
TU Wien, Austria
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dc.contributor.affiliation
Aarhus University, Denmark
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dc.contributor.affiliation
TU Wien, Austria
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dc.relation.grantno
PAT8221324
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dc.type.category
Conference Presentation
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tuw.project.title
Matrix Isolation von atmosphärischen Nukleationsclustern
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tuw.researchTopic.id
E4
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tuw.researchTopic.name
Environmental Monitoring and Climate Adaptation
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tuw.researchTopic.value
100
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tuw.publication.orgunit
E165-01-5 - Forschungsgruppe Physikalische Chemie von Aerosolpartikeln
