The Gas-Phase Infrared Spectra of Xylyl Radicals

Florian Hirsch, Marco Flock, Ingo Fischer*, Sjors Bakels, Anouk M. Rijs

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


The three isomers of the xylyl radical, C8H9, are possible intermediates in the formation of soot and polycyclic aromatic hydrocarbons (PAH). Their infrared spectra have been recorded by IR/UV ion dip spectroscopy using free electron laser radiation. The radicals were generated by flash pyrolysis from the corresponding nitrites and resonantly ionized via the D3 ↠D0 transition around 310 nm. Mid-infrared spectra of the three xylyl isomers were recorded between 550 and 1700 cm-1 and are in excellent agreement with computations, provided that overtones and combination bands are included in the simulation. The results show that the three xylyl isomers can be distinguished by their infrared spectra and that no isomerization occurs in the pyrolysis reactor. The IR spectra obtained at m/z = 208 indicate that dimerization of xylyl radicals leads to substituted stilbenes, which has not been observed for benzyl.

Original languageEnglish
Pages (from-to)9573-9578
Number of pages6
JournalJournal of Physical Chemistry A
Issue number44
Publication statusPublished - 7 Nov 2019
Externally publishedYes


This work was financially supported by the Deutsche Forschungsgemeinschaft, Research Training Group GRK2112. Furthermore, the research leading to these results has received funding from LASERLAB-EUROPE (grant agreement no. 654148, European Union’s Horizon 2020 research and innovation programme). We gratefully thank the FELIX staff for their experimental support and we acknowledge the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) for the support of the FELIX Laboratory.

FundersFunder number
Horizon 2020 Framework Programme654148
Deutsche ForschungsgemeinschaftGRK2112
Horizon 2020


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