Hannover 2016 – scientific programme

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MO: Fachverband Molekülphysik

MO 9: Biomolecules and Photochemistry

MO 9.6: Talk

Tuesday, March 1, 2016, 16:00–16:15, f102

The Photodissociation of the Ortho-Xylyl Radical, C8H9, Investigated by Velocity Map Imaging — •Kai Pachner and Ingo Fischer — Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland Süd, 97074 Würzburg, Deutschland

Xylyl radicals can be found as intermediates in combustion processes. Their parent molecules, the xylenes, are used as additives in fuels to increase antiknock properties. The thermal decomposition of the xylyl radicals has been explored recently by Hemberger et al. in a synchrotron experiment [1]. Based on these studies, we investigated the photodissociation of the ortho-xylyl radical using velocity map imaging. Ortho-xylyl radicals were formed via flash pyrolysis in a pulsed molecular beam using 2-methylphenethyl nitrite as a precursor. Irradiation of the ortho-xylyl radical with UV light leads to the formation of either ortho-xylylene or benzocyclobutene by hydrogen atom loss. Generated hydrogen fragments are then ionized in a [1+1']-REMPI process via the 1s-2p transition and detected on a velocity map imaging detector. The translational energy distribution of the hydrogen fragments as well as their angular distribution indicate a statistical dissociation for both pathways.

[1] Hemberger et al., J. Phys. Chem. A, 2014, 118, 3593 - 3604.