Freiburg 2024 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 7: Poster: Spectroscopy

MO 7.6: Poster

Dienstag, 12. März 2024, 17:00–19:00, Tent C

Photodissociation dynamics of the CHCl₂ radical — •Jonas Fackelmayer and Ingo Fischer — Julius-Maximilians-Universität Würzburg, 97074 Würzburg, Germany

Monitoring the atmospheric abundances of the ozone-depleting CFCs has revealed a global increase in emission of these banned substances.^[1] Meanwhile the dimensions of the ozone-hole have been reported to be at a all time high in 2023.^[2] This makes the photodissociation of these compounds of great importance since it often results in the release of highly reactive halogen radicals. While the dissociation dynamics of molecular halocarbons have been studied in detail in the past, less is known about their open shell counterparts.

The photofragmentation of the open shell CHCl₂, generated by pyrolysis from the bromide and iodide precursors CHCl₂Br/CHCl₂I, was investigated in a free jet utilising time-of-flight mass-spectrometry and velocity map imaging. Photodissociation was achieved by a pulsed dye laser in the range of 230 - 250 nm mainly producing CHCl and Cl fragments, while ionisation was provided by either a second dye laser (REMPI) or a frequency multiplied solid state laser at 118 nm (SPI). Insights into the involved dissociation mechanisms are discussed.

[1] L. M. Western al., Nat. Geosci. 2023, 16, 309*313.

[2] European Space Agency, Ozone hole goes large again, 2023.

Keywords: radical; velocity map imaging; time-of-flight mass-spectrometry; atmosphere